/// <summary>
        /// Adds TableRow elements to xamlTableBodyElement. The rows are converted from Html tr elements that
        /// may be the children of an Html tbody element or an Html table element with tbody missing
        /// </summary>
        /// <param name="xamlTableBodyElement">
        /// XmlElement representing Xaml TableRowGroup element to which the converted rows should be added
        /// </param>
        /// <param name="htmlTRStartNode">
        /// XmlElement representing the first tr child of the tbody element to be read
        /// </param>
        /// <param name="currentProperties">
        /// Hashtable representing current properties of the tbody element that are generated and applied in the
        /// AddTable function; to be used as inheritedProperties when adding tr elements
        /// </param>
        /// <param name="columnStarts"></param>
        /// <param name="stylesheet"></param>
        /// <param name="sourceContext"></param>
        /// <returns>
        /// XmlNode representing the current position of the iterator among tr elements
        /// </returns>
        private static XmlNode AddTableRowsToTableBody(XmlElement xamlTableBodyElement, XmlNode htmlTRStartNode, Hashtable currentProperties, ArrayList columnStarts, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            // Parameter validation
            Debug.Assert(xamlTableBodyElement.LocalName == Xaml_TableRowGroup);
            Debug.Assert(currentProperties != null);

            // Initialize child node for iteratimg through children to the first tr element
            XmlNode htmlChildNode = htmlTRStartNode;
            ArrayList activeRowSpans = null;
            if(columnStarts != null) {
                activeRowSpans = new ArrayList();
                InitializeActiveRowSpans(activeRowSpans, columnStarts.Count);
            }

            while(htmlChildNode != null && htmlChildNode.LocalName.ToLower() != "tbody") {
                if(htmlChildNode.LocalName.ToLower() == "tr") {
                    XmlElement xamlTableRowElement = xamlTableBodyElement.OwnerDocument.CreateElement(null, Xaml_TableRow, _xamlNamespace);

                    sourceContext.Add((XmlElement)htmlChildNode);

                    // Get tr element properties
                    Hashtable trElementLocalProperties;
                    Hashtable trElementCurrentProperties = GetElementProperties((XmlElement)htmlChildNode, currentProperties, out trElementLocalProperties, stylesheet, sourceContext);
                    // TODO: apply local properties to tr element

                    AddTableCellsToTableRow(xamlTableRowElement, htmlChildNode.FirstChild, trElementCurrentProperties, columnStarts, activeRowSpans, stylesheet, sourceContext);
                    if(xamlTableRowElement.HasChildNodes) {
                        xamlTableBodyElement.AppendChild(xamlTableRowElement);
                    }

                    Debug.Assert(sourceContext.Count > 0 && sourceContext[sourceContext.Count - 1] == htmlChildNode);
                    sourceContext.RemoveAt(sourceContext.Count - 1);

                    // Advance
                    htmlChildNode = htmlChildNode.NextSibling;

                } else if(htmlChildNode.LocalName.ToLower() == "td") {
                    // Tr element is not present. We create one and add td elements to it
                    XmlElement xamlTableRowElement = xamlTableBodyElement.OwnerDocument.CreateElement(null, Xaml_TableRow, _xamlNamespace);

                    // This is incorrect formatting and the column starts should not be set in this case
                    Debug.Assert(columnStarts == null);

                    htmlChildNode = AddTableCellsToTableRow(xamlTableRowElement, htmlChildNode, currentProperties, columnStarts, activeRowSpans, stylesheet, sourceContext);
                    if(xamlTableRowElement.HasChildNodes) {
                        xamlTableBodyElement.AppendChild(xamlTableRowElement);
                    }
                } else {
                    // Not a tr or td  element. Ignore it.
                    // TODO: consider better recovery here
                    htmlChildNode = htmlChildNode.NextSibling;
                }
            }
            return htmlChildNode;
        }
        /// <summary>
        /// Performs a parsing pass over a table to read information about column width and rowspan attributes. This information
        /// is used to determine the starting point of each column.
        /// </summary>
        /// <param name="htmlTableElement">
        /// XmlElement representing Html table whose structure is to be analyzed
        /// </param>
        /// <returns>
        /// ArrayList of type double which contains the function output. If analysis is successful, this ArrayList contains
        /// all the points which are the starting position of any column in the table, ordered from left to right.
        /// In case if analisys was impossible we return null.
        /// </returns>
        private static ArrayList AnalyzeTableStructure(XmlElement htmlTableElement, CssStylesheet stylesheet)
        {
            // Parameter validation
            Debug.Assert(htmlTableElement.LocalName.ToLower() == "table");
            if(!htmlTableElement.HasChildNodes) {
                return null;
            }

            bool columnWidthsAvailable = true;

            ArrayList columnStarts = new ArrayList();
            ArrayList activeRowSpans = new ArrayList();
            Debug.Assert(columnStarts.Count == activeRowSpans.Count);

            XmlNode htmlChildNode = htmlTableElement.FirstChild;
            double tableWidth = 0;  // Keep track of table width which is the width of its widest row

            // Analyze tbody and tr elements
            while(htmlChildNode != null && columnWidthsAvailable) {
                Debug.Assert(columnStarts.Count == activeRowSpans.Count);

                switch(htmlChildNode.LocalName.ToLower()) {
                    case "tbody":
                        // Tbody element, we should analyze its children for trows
                        double tbodyWidth = AnalyzeTbodyStructure((XmlElement)htmlChildNode, columnStarts, activeRowSpans, tableWidth, stylesheet);
                        if(tbodyWidth > tableWidth) {
                            // Table width must be increased to supported newly added wide row
                            tableWidth = tbodyWidth;
                        } else if(tbodyWidth == 0) {
                            // Tbody analysis may return 0, probably due to unprocessable format.
                            // We should also fail.
                            columnWidthsAvailable = false; // interrupt the analisys
                        }
                        break;
                    case "tr":
                        // Table row. Analyze column structure within row directly
                        double trWidth = AnalyzeTRStructure((XmlElement)htmlChildNode, columnStarts, activeRowSpans, tableWidth, stylesheet);
                        if(trWidth > tableWidth) {
                            tableWidth = trWidth;
                        } else if(trWidth == 0) {
                            columnWidthsAvailable = false; // interrupt the analisys
                        }
                        break;
                    case "td":
                        // Incorrect formatting, too deep to analyze at this level. Return null.
                        // TODO: implement analysis at this level, possibly by creating a new tr
                        columnWidthsAvailable = false; // interrupt the analisys
                        break;
                    default:
                        // Element should not occur directly in table. Ignore it.
                        break;
                }

                htmlChildNode = htmlChildNode.NextSibling;
            }

            if(columnWidthsAvailable) {
                // Add an item for whole table width
                columnStarts.Add(tableWidth);
                VerifyColumnStartsAscendingOrder(columnStarts);
            } else {
                columnStarts = null;
            }

            return columnStarts;
        }
        private static void AddHyperlink(XmlElement xamlParentElement, XmlElement htmlElement, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            // Convert href attribute into NavigateUri and TargetName
            string href = GetAttribute(htmlElement, "href");
            if(href == null) {
                // When href attribute is missing - ignore the hyperlink
                AddSpanOrRun(xamlParentElement, htmlElement, inheritedProperties, stylesheet, sourceContext);
            } else {
                // Create currentProperties as a compilation of local and inheritedProperties, set localProperties
                Hashtable localProperties;
                Hashtable currentProperties = GetElementProperties(htmlElement, inheritedProperties, out localProperties, stylesheet, sourceContext);

                // Create a XAML element corresponding to this html element
                XmlElement xamlElement = xamlParentElement.OwnerDocument.CreateElement(/*prefix:*/null, /*localName:*/HtmlToXamlConverter.Xaml_Hyperlink, _xamlNamespace);
                ApplyLocalProperties(xamlElement, localProperties, /*isBlock:*/false);

                string[] hrefParts = href.Split(new char[] { '#' });
                if(hrefParts.Length > 0 && hrefParts[0].Trim().Length > 0) {
                    xamlElement.SetAttribute(HtmlToXamlConverter.Xaml_Hyperlink_NavigateUri, hrefParts[0].Trim());
                }
                if(hrefParts.Length == 2 && hrefParts[1].Trim().Length > 0) {
                    xamlElement.SetAttribute(HtmlToXamlConverter.Xaml_Hyperlink_TargetName, hrefParts[1].Trim());
                }

                // Recurse into element subtree
                for(XmlNode htmlChildNode = htmlElement.FirstChild; htmlChildNode != null; htmlChildNode = htmlChildNode.NextSibling) {
                    AddInline(xamlElement, htmlChildNode, currentProperties, stylesheet, sourceContext);
                }

                // Add the new element to the parent.
                xamlParentElement.AppendChild(xamlElement);
            }
        }
        /// <summary>
        /// Creates a Paragraph element and adds all nodes starting from htmlNode
        /// converted to appropriate Inlines.
        /// </summary>
        /// <param name="xamlParentElement">
        /// XmlElement representing Xaml parent to which the converted element should be added
        /// </param>
        /// <param name="htmlNode">
        /// XmlNode starting a collection of implicitly wrapped inlines.
        /// </param>
        /// <param name="inheritedProperties">
        /// properties inherited from parent context
        /// </param>
        /// <param name="stylesheet"></param>
        /// <param name="sourceContext"></param>
        /// true indicates that a content added by this call contains at least one block element
        /// </param>
        /// <returns>
        /// The last htmlNode added to the implicit paragraph
        /// </returns>
        private static XmlNode AddImplicitParagraph(XmlElement xamlParentElement, XmlNode htmlNode, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            // Collect all non-block elements and wrap them into implicit Paragraph
            XmlElement xamlParagraph = xamlParentElement.OwnerDocument.CreateElement(/*prefix:*/null, /*localName:*/HtmlToXamlConverter.Xaml_Paragraph, _xamlNamespace);
            XmlNode lastNodeProcessed = null;
            while(htmlNode != null) {
                if(htmlNode is XmlComment) {
                    DefineInlineFragmentParent((XmlComment)htmlNode, /*xamlParentElement:*/null);
                } else if(htmlNode is XmlText) {
                    if(htmlNode.Value.Trim().Length > 0) {
                        AddTextRun(xamlParagraph, htmlNode.Value);
                    }
                } else if(htmlNode is XmlElement) {
                    string htmlChildName = ((XmlElement)htmlNode).LocalName.ToLower();
                    if(HtmlSchema.IsBlockElement(htmlChildName)) {
                        // The sequence of non-blocked inlines ended. Stop implicit loop here.
                        break;
                    } else {
                        AddInline(xamlParagraph, (XmlElement)htmlNode, inheritedProperties, stylesheet, sourceContext);
                    }
                }

                // Store last processed node to return it at the end
                lastNodeProcessed = htmlNode;
                htmlNode = htmlNode.NextSibling;
            }

            // Add the Paragraph to the parent
            // If only whitespaces and commens have been encountered,
            // then we have nothing to add in implicit paragraph; forget it.
            if(xamlParagraph.FirstChild != null) {
                xamlParentElement.AppendChild(xamlParagraph);
            }

            // Need to return last processed node
            return lastNodeProcessed;
        }
        /// <summary>
        /// Converts an html string into xaml string.
        /// </summary>
        /// <param name="htmlString">
        /// Input html which may be badly formated xml.
        /// </param>
        /// <param name="asFlowDocument">
        /// true indicates that we need a FlowDocument as a root element;
        /// false means that Section or Span elements will be used
        /// dependeing on StartFragment/EndFragment comments locations.
        /// </param>
        /// <returns>
        /// Well-formed xml representing XAML equivalent for the input html string.
        /// </returns>
        public static string ConvertHtmlToXaml(string htmlString, bool asFlowDocument)
        {
            // Create well-formed Xml from Html string
            XmlElement htmlElement = HtmlParser.ParseHtml(htmlString);

            ReplaceInvalidThings(htmlElement);
            // Decide what name to use as a root
            string rootElementName = asFlowDocument ? Xaml_FlowDocument : Xaml_Section;

            // Create an XmlDocument for generated xaml
            XmlDocument xamlTree = new XmlDocument();
            XmlElement xamlFlowDocumentElement = xamlTree.CreateElement(null, rootElementName, _xamlNamespace);

            // Extract style definitions from all STYLE elements in the document
            CssStylesheet stylesheet = new CssStylesheet(htmlElement);

            // Source context is a stack of all elements - ancestors of a parentElement
            List<XmlElement> sourceContext = new List<XmlElement>(10);

            // Clear fragment parent
            InlineFragmentParentElement = null;

            // convert root html element
            AddBlock(xamlFlowDocumentElement, htmlElement, new Hashtable(), stylesheet, sourceContext);

            // In case if the selected fragment is inline, extract it into a separate Span wrapper
            if(!asFlowDocument) {
                xamlFlowDocumentElement = ExtractInlineFragment(xamlFlowDocumentElement);
            }

            // Return a string representing resulting Xaml
            xamlFlowDocumentElement.SetAttribute("xml:space", "preserve");
            string xaml = xamlFlowDocumentElement.OuterXml;

            return xaml;
        }
        /// <summary>
        /// Processes the information about table columns - COLGROUP and COL html elements.
        /// </summary>
        /// <param name="htmlTableElement">
        /// XmlElement representing a source html table.
        /// </param>
        /// <param name="xamlTableElement">
        /// XmlElement repesenting a resulting xaml table.
        /// </param>
        /// <param name="columnStartsAllRows">
        /// Array of doubles - column start coordinates.
        /// Can be null, which means that column size information is not available
        /// and we must use source colgroup/col information.
        /// In case wneh it's not null, we will ignore source colgroup/col information.
        /// </param>
        /// <param name="currentProperties"></param>
        /// <param name="stylesheet"></param>
        /// <param name="sourceContext"></param>
        private static void AddColumnInformation(XmlElement htmlTableElement, XmlElement xamlTableElement, ArrayList columnStartsAllRows, Hashtable currentProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            // Add column information
            if(columnStartsAllRows != null) {
                // We have consistent information derived from table cells; use it
                // The last element in columnStarts represents the end of the table
                for(int columnIndex = 0; columnIndex < columnStartsAllRows.Count - 1; columnIndex++) {
                    XmlElement xamlColumnElement;

                    xamlColumnElement = xamlTableElement.OwnerDocument.CreateElement(null, Xaml_TableColumn, _xamlNamespace);
                    xamlColumnElement.SetAttribute(Xaml_Width, ((double)columnStartsAllRows[columnIndex + 1] - (double)columnStartsAllRows[columnIndex]).ToString());
                    xamlTableElement.AppendChild(xamlColumnElement);
                }
            } else {
                // We do not have consistent information from table cells;
                // Translate blindly colgroups from html.
                for(XmlNode htmlChildNode = htmlTableElement.FirstChild; htmlChildNode != null; htmlChildNode = htmlChildNode.NextSibling) {
                    if(htmlChildNode.LocalName.ToLower() == "colgroup") {
                        // TODO: add column width information to this function as a parameter and process it
                        AddTableColumnGroup(xamlTableElement, (XmlElement)htmlChildNode, currentProperties, stylesheet, sourceContext);
                    } else if(htmlChildNode.LocalName.ToLower() == "col") {
                        AddTableColumn(xamlTableElement, (XmlElement)htmlChildNode, currentProperties, stylesheet, sourceContext);
                    } else if(htmlChildNode is XmlElement) {
                        // Some element which belongs to table body. Stop column loop.
                        break;
                    }
                }
            }
        }
        // .............................................................
        //
        // Text Flow Elements
        //
        // .............................................................
        /// <summary>
        /// Generates Section or Paragraph element from DIV depending whether it contains any block elements or not
        /// </summary>
        /// <param name="xamlParentElement">
        /// XmlElement representing Xaml parent to which the converted element should be added
        /// </param>
        /// <param name="htmlElement">
        /// XmlElement representing Html element to be converted
        /// </param>
        /// <param name="inheritedProperties">
        /// properties inherited from parent context
        /// </param>
        /// <param name="stylesheet"></param>
        /// <param name="sourceContext"></param>
        /// true indicates that a content added by this call contains at least one block element
        /// </param>
        private static void AddSection(XmlElement xamlParentElement, XmlElement htmlElement, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            // Analyze the content of htmlElement to decide what xaml element to choose - Section or Paragraph.
            // If this Div has at least one block child then we need to use Section, otherwise use Paragraph
            bool htmlElementContainsBlocks = false;
            for(XmlNode htmlChildNode = htmlElement.FirstChild; htmlChildNode != null; htmlChildNode = htmlChildNode.NextSibling) {
                if(htmlChildNode is XmlElement) {
                    string htmlChildName = ((XmlElement)htmlChildNode).LocalName.ToLower();
                    if(HtmlSchema.IsBlockElement(htmlChildName)) {
                        htmlElementContainsBlocks = true;
                        break;
                    }
                }
            }

            if(!htmlElementContainsBlocks) {
                // The Div does not contain any block elements, so we can treat it as a Paragraph
                AddParagraph(xamlParentElement, htmlElement, inheritedProperties, stylesheet, sourceContext);
            } else {
                // The Div has some nested blocks, so we treat it as a Section

                // Create currentProperties as a compilation of local and inheritedProperties, set localProperties
                Hashtable localProperties;
                Hashtable currentProperties = GetElementProperties(htmlElement, inheritedProperties, out localProperties, stylesheet, sourceContext);

                // Create a XAML element corresponding to this html element
                XmlElement xamlElement = xamlParentElement.OwnerDocument.CreateElement(/*prefix:*/null, /*localName:*/HtmlToXamlConverter.Xaml_Section, _xamlNamespace);
                ApplyLocalProperties(xamlElement, localProperties, /*isBlock:*/true);

                // Decide whether we can unwrap this element as not having any formatting significance.
                if(!xamlElement.HasAttributes) {
                    // This elements is a group of block elements whitout any additional formatting.
                    // We can add blocks directly to xamlParentElement and avoid
                    // creating unnecessary Sections nesting.
                    xamlElement = xamlParentElement;
                }

                // Recurse into element subtree
                for(XmlNode htmlChildNode = htmlElement.FirstChild; htmlChildNode != null; htmlChildNode = htmlChildNode != null ? htmlChildNode.NextSibling : null) {
                    htmlChildNode = AddBlock(xamlElement, htmlChildNode, currentProperties, stylesheet, sourceContext);
                }

                // Add the new element to the parent.
                if(xamlElement != xamlParentElement) {
                    xamlParentElement.AppendChild(xamlElement);
                }
            }
        }
        /// <summary>
        /// Analyzes the tag of the htmlElement and infers its associated formatted properties.
        /// After that parses style attribute and adds all inline css styles.
        /// The resulting style attributes are collected in output parameter localProperties.
        /// </summary>
        /// <param name="htmlElement">
        /// </param>
        /// <param name="inheritedProperties">
        /// set of properties inherited from ancestor elements. Currently not used in the code. Reserved for the future development.
        /// </param>
        /// <param name="localProperties">
        /// returns all formatting properties defined by this element - implied by its tag, its attributes, or its css inline style
        /// </param>
        /// <param name="stylesheet"></param>
        /// <param name="sourceContext"></param>
        /// <returns>
        /// returns a combination of previous context with local set of properties.
        /// This value is not used in the current code - inntended for the future development.
        /// </returns>
        private static Hashtable GetElementProperties(XmlElement htmlElement, Hashtable inheritedProperties, out Hashtable localProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            // Start with context formatting properties
            Hashtable currentProperties = new Hashtable();
            IDictionaryEnumerator propertyEnumerator = inheritedProperties.GetEnumerator();
            while(propertyEnumerator.MoveNext()) {
                currentProperties[propertyEnumerator.Key] = propertyEnumerator.Value;
            }

            // Identify element name
            string elementName = htmlElement.LocalName.ToLower();
            string elementNamespace = htmlElement.NamespaceURI;

            // update current formatting properties depending on element tag

            localProperties = new Hashtable();
            switch(elementName) {
                // Character formatting
                case "i":
                case "italic":
                case "em":
                    localProperties["font-style"] = "italic";
                    break;
                case "b":
                case "bold":
                case "strong":
                case "dfn":
                    localProperties["font-weight"] = "bold";
                    break;
                case "u":
                case "underline":
                    localProperties["text-decoration-underline"] = "true";
                    break;
                case "font":
                    string attributeValue = GetAttribute(htmlElement, "face");
                    if(attributeValue != null) {
                        localProperties["font-family"] = attributeValue;
                    }
                    attributeValue = GetAttribute(htmlElement, "size");
                    if(attributeValue != null) {
                        /* fontタグ size属性は無効にする
                        double fontSize = double.Parse(attributeValue) * (12.0 / 3.0);
                        if(fontSize < 1.0) {
                            fontSize = 1.0;
                        } else if(fontSize > 1000.0) {
                            fontSize = 1000.0;
                        }
                        localProperties["font-size"] = fontSize.ToString();
                        */
                    }
                    attributeValue = GetAttribute(htmlElement, "color");
                    if(attributeValue != null) {
                        localProperties["color"] = attributeValue;
                    }
                    break;
                case "samp":
                    localProperties["font-family"] = "Courier New"; // code sample
                    localProperties["font-size"] = Xaml_FontSize_XXSmall;
                    localProperties["text-align"] = "Left";
                    break;
                case "sub":
                    break;
                case "sup":
                    break;

                // Hyperlinks
                case "a": // href, hreflang, urn, methods, rel, rev, title
                    //  Set default hyperlink properties
                    break;
                case "acronym":
                    break;

                // Paragraph formatting:
                case "p":
                    //  Set default paragraph properties
                    break;
                case "div":
                    //  Set default div properties
                    break;
                case "pre":
                    localProperties["font-family"] = "Courier New"; // renders text in a fixed-width font
                    localProperties["font-size"] = Xaml_FontSize_XXSmall;
                    localProperties["text-align"] = "Left";
                    break;
                case "blockquote":
                    localProperties["margin-left"] = "16";
                    break;

                case "h1":
                    localProperties["font-size"] = Xaml_FontSize_XXLarge;
                    break;
                case "h2":
                    localProperties["font-size"] = Xaml_FontSize_XLarge;
                    break;
                case "h3":
                    localProperties["font-size"] = Xaml_FontSize_Large;
                    break;
                case "h4":
                    localProperties["font-size"] = Xaml_FontSize_Medium;
                    break;
                case "h5":
                    localProperties["font-size"] = Xaml_FontSize_Small;
                    break;
                case "h6":
                    localProperties["font-size"] = Xaml_FontSize_XSmall;
                    break;
                // List properties
                case "ul":
                    localProperties["list-style-type"] = "disc";
                    break;
                case "ol":
                    localProperties["list-style-type"] = "decimal";
                    break;

                case "table":
                case "body":
                case "html":
                    break;
            }

            // Override html defaults by css attributes - from stylesheets and inline settings
            HtmlCssParser.GetElementPropertiesFromCssAttributes(htmlElement, elementName, stylesheet, localProperties, sourceContext);

            // Combine local properties with context to create new current properties
            propertyEnumerator = localProperties.GetEnumerator();
            while(propertyEnumerator.MoveNext()) {
                currentProperties[propertyEnumerator.Key] = propertyEnumerator.Value;
            }

            return currentProperties;
        }
        /// <summary>
        /// If li items are found without a parent ul/ol element in Html string, creates xamlListElement as their parent and adds
        /// them to it. If the previously added node to the same xamlParentElement was a List, adds the elements to that list.
        /// Otherwise, we create a new xamlListElement and add them to it. Elements are added as long as li elements appear sequentially.
        /// The first non-li or text node stops the addition.
        /// </summary>
        /// <param name="xamlParentElement">
        /// Parent element for the list
        /// </param>
        /// <param name="htmlLIElement">
        /// Start Html li element without parent list
        /// </param>
        /// <param name="inheritedProperties">
        /// Properties inherited from parent context
        /// </param>
        /// <returns>
        /// XmlNode representing the first non-li node in the input after one or more li's have been processed.
        /// </returns>
        private static XmlElement AddOrphanListItems(XmlElement xamlParentElement, XmlElement htmlLIElement, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            Debug.Assert(htmlLIElement.LocalName.ToLower() == "li");

            XmlElement lastProcessedListItemElement = null;

            // Find out the last element attached to the xamlParentElement, which is the previous sibling of this node
            XmlNode xamlListItemElementPreviousSibling = xamlParentElement.LastChild;
            XmlElement xamlListElement;
            if(xamlListItemElementPreviousSibling != null && xamlListItemElementPreviousSibling.LocalName == Xaml_List) {
                // Previously added Xaml element was a list. We will add the new li to it
                xamlListElement = (XmlElement)xamlListItemElementPreviousSibling;
            } else {
                // No list element near. Create our own.
                xamlListElement = xamlParentElement.OwnerDocument.CreateElement(null, Xaml_List, _xamlNamespace);
                xamlParentElement.AppendChild(xamlListElement);
            }

            XmlNode htmlChildNode = htmlLIElement;
            string htmlChildNodeName = htmlChildNode == null ? null : htmlChildNode.LocalName.ToLower();

            //  Current element properties missed here.
            //currentProperties = GetElementProperties(htmlLIElement, inheritedProperties, out localProperties, stylesheet);

            // Add li elements to the parent xamlListElement we created as long as they appear sequentially
            // Use properties inherited from xamlParentElement for context
            while(htmlChildNode != null && htmlChildNodeName == "li") {
                AddListItem(xamlListElement, (XmlElement)htmlChildNode, inheritedProperties, stylesheet, sourceContext);
                lastProcessedListItemElement = (XmlElement)htmlChildNode;
                htmlChildNode = htmlChildNode.NextSibling;
                htmlChildNodeName = htmlChildNode == null ? null : htmlChildNode.LocalName.ToLower();
            }

            return lastProcessedListItemElement;
        }
        /// <summary>
        /// Generates Paragraph element from P, H1-H7, Center etc.
        /// </summary>
        /// <param name="xamlParentElement">
        /// XmlElement representing Xaml parent to which the converted element should be added
        /// </param>
        /// <param name="htmlElement">
        /// XmlElement representing Html element to be converted
        /// </param>
        /// <param name="inheritedProperties">
        /// properties inherited from parent context
        /// </param>
        /// <param name="stylesheet"></param>
        /// <param name="sourceContext"></param>
        /// true indicates that a content added by this call contains at least one block element
        /// </param>
        private static void AddParagraph(XmlElement xamlParentElement, XmlElement htmlElement, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            // Create currentProperties as a compilation of local and inheritedProperties, set localProperties
            Hashtable localProperties;
            Hashtable currentProperties = GetElementProperties(htmlElement, inheritedProperties, out localProperties, stylesheet, sourceContext);

            // Create a XAML element corresponding to this html element
            XmlElement xamlElement = xamlParentElement.OwnerDocument.CreateElement(/*prefix:*/null, /*localName:*/HtmlToXamlConverter.Xaml_Paragraph, _xamlNamespace);
            ApplyLocalProperties(xamlElement, localProperties, /*isBlock:*/true);

            // Recurse into element subtree
            for(XmlNode htmlChildNode = htmlElement.FirstChild; htmlChildNode != null; htmlChildNode = htmlChildNode.NextSibling) {

                AddInline(xamlElement, htmlChildNode, currentProperties, stylesheet, sourceContext);
            }

            // Add the new element to the parent.
            xamlParentElement.AppendChild(xamlElement);
        }
        /// <summary>
        /// Converts htmlLIElement into Xaml ListItem element, and appends it to the parent xamlListElement
        /// </summary>
        /// <param name="xamlListElement">
        /// XmlElement representing Xaml List element to which the converted td/th should be added
        /// </param>
        /// <param name="htmlLIElement">
        /// XmlElement representing Html li element to be converted
        /// </param>
        /// <param name="inheritedProperties">
        /// Properties inherited from parent context
        /// </param>
        private static void AddListItem(XmlElement xamlListElement, XmlElement htmlLIElement, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            // Parameter validation
            Debug.Assert(xamlListElement != null);
            Debug.Assert(xamlListElement.LocalName == Xaml_List);
            Debug.Assert(htmlLIElement != null);
            Debug.Assert(htmlLIElement.LocalName.ToLower() == "li");
            Debug.Assert(inheritedProperties != null);

            Hashtable localProperties;
            Hashtable currentProperties = GetElementProperties(htmlLIElement, inheritedProperties, out localProperties, stylesheet, sourceContext);

            XmlElement xamlListItemElement = xamlListElement.OwnerDocument.CreateElement(null, Xaml_ListItem, _xamlNamespace);

            // TODO: process local properties for li element

            // Process children of the ListItem
            for(XmlNode htmlChildNode = htmlLIElement.FirstChild; htmlChildNode != null; htmlChildNode = htmlChildNode != null ? htmlChildNode.NextSibling : null) {
                htmlChildNode = AddBlock(xamlListItemElement, htmlChildNode, currentProperties, stylesheet, sourceContext);
            }

            // Add resulting ListBoxItem to a xaml parent
            xamlListElement.AppendChild(xamlListItemElement);
        }
        // .............................................................
        //
        // Lists
        //
        // .............................................................
        /// <summary>
        /// Converts Html ul or ol element into Xaml list element. During conversion if the ul/ol element has any children
        /// that are not li elements, they are ignored and not added to the list element
        /// </summary>
        /// <param name="xamlParentElement">
        /// XmlElement representing Xaml parent to which the converted element should be added
        /// </param>
        /// <param name="htmlListElement">
        /// XmlElement representing Html ul/ol element to be converted
        /// </param>
        /// <param name="inheritedProperties">
        /// properties inherited from parent context
        /// </param>
        /// <param name="stylesheet"></param>
        /// <param name="sourceContext"></param>
        private static void AddList(XmlElement xamlParentElement, XmlElement htmlListElement, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            string htmlListElementName = htmlListElement.LocalName.ToLower();

            Hashtable localProperties;
            Hashtable currentProperties = GetElementProperties(htmlListElement, inheritedProperties, out localProperties, stylesheet, sourceContext);

            // Create Xaml List element
            XmlElement xamlListElement = xamlParentElement.OwnerDocument.CreateElement(null, Xaml_List, _xamlNamespace);

            // Set default list markers
            if(htmlListElementName == "ol") {
                // Ordered list
                xamlListElement.SetAttribute(HtmlToXamlConverter.Xaml_List_MarkerStyle, Xaml_List_MarkerStyle_Decimal);
            } else {
                // Unordered list - all elements other than OL treated as unordered lists
                xamlListElement.SetAttribute(HtmlToXamlConverter.Xaml_List_MarkerStyle, Xaml_List_MarkerStyle_Disc);
            }

            // Apply local properties to list to set marker attribute if specified
            // TODO: Should we have separate list attribute processing function?
            ApplyLocalProperties(xamlListElement, localProperties, /*isBlock:*/true);

            // Recurse into list subtree
            for(XmlNode htmlChildNode = htmlListElement.FirstChild; htmlChildNode != null; htmlChildNode = htmlChildNode.NextSibling) {
                if(htmlChildNode is XmlElement && htmlChildNode.LocalName.ToLower() == "li") {
                    sourceContext.Add((XmlElement)htmlChildNode);
                    AddListItem(xamlListElement, (XmlElement)htmlChildNode, currentProperties, stylesheet, sourceContext);
                    Debug.Assert(sourceContext.Count > 0 && sourceContext[sourceContext.Count - 1] == htmlChildNode);
                    sourceContext.RemoveAt(sourceContext.Count - 1);
                } else {
                    // Not an li element. Add it to previous ListBoxItem
                    //  We need to append the content to the end
                    // of a previous list item.
                }
            }

            // Add the List element to xaml tree - if it is not empty
            if(xamlListElement.HasChildNodes) {
                xamlParentElement.AppendChild(xamlListElement);
            }
        }
        // .............................................................
        //
        // Inline Elements
        //
        // .............................................................
        private static void AddInline(XmlElement xamlParentElement, XmlNode htmlNode, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            if(htmlNode is XmlComment) {
                DefineInlineFragmentParent((XmlComment)htmlNode, xamlParentElement);
            } else if(htmlNode is XmlText) {
                AddTextRun(xamlParentElement, htmlNode.Value);
            } else if(htmlNode is XmlElement) {
                XmlElement htmlElement = (XmlElement)htmlNode;

                // Check whether this is an html element
                if(htmlElement.NamespaceURI != HtmlParser.XhtmlNamespace) {
                    return; // Skip non-html elements
                }

                // Identify element name
                string htmlElementName = htmlElement.LocalName.ToLower();

                // Put source element to the stack
                sourceContext.Add(htmlElement);

                switch(htmlElementName) {
                    case "a":
                        AddHyperlink(xamlParentElement, htmlElement, inheritedProperties, stylesheet, sourceContext);
                        break;
                    case "img":
                        AddImage(xamlParentElement, htmlElement, inheritedProperties, stylesheet, sourceContext);
                        break;
                    case "br":
                    case "hr":
                        AddBreak(xamlParentElement, htmlElementName);
                        break;
                    default:
                        if(HtmlSchema.IsInlineElement(htmlElementName) || HtmlSchema.IsBlockElement(htmlElementName)) {
                            // Note: actually we do not expect block elements here,
                            // but if it happens to be here, we will treat it as a Span.

                            AddSpanOrRun(xamlParentElement, htmlElement, inheritedProperties, stylesheet, sourceContext);
                        }
                        break;
                }
                // Ignore all other elements non-(block/inline/image)

                // Remove the element from the stack
                Debug.Assert(sourceContext.Count > 0 && sourceContext[sourceContext.Count - 1] == htmlElement);
                sourceContext.RemoveAt(sourceContext.Count - 1);
            }
        }
        /// <summary>
        /// Performs a parsing pass over a tbody to read information about column width and rowspan attributes. Information read about width
        /// attributes is stored in the reference ArrayList parameter columnStarts, which contains a list of all starting
        /// positions of all columns in the table, ordered from left to right. Row spans are taken into consideration when
        /// computing column starts
        /// </summary>
        /// <param name="htmlTbodyElement">
        /// XmlElement representing Html tbody whose structure is to be analyzed
        /// </param>
        /// <param name="columnStarts">
        /// ArrayList of type double which contains the function output. If analysis fails, this parameter is set to null
        /// </param>
        /// <param name="tableWidth">
        /// Current width of the table. This is used to determine if a new column when added to the end of table should
        /// come after the last column in the table or is actually splitting the last column in two. If it is only splitting
        /// the last column it should inherit row span for that column
        /// </param>
        /// <returns>
        /// Calculated width of a tbody.
        /// In case of non-analizable column width structure return 0;
        /// </returns>
        private static double AnalyzeTbodyStructure(XmlElement htmlTbodyElement, ArrayList columnStarts, ArrayList activeRowSpans, double tableWidth, CssStylesheet stylesheet)
        {
            // Parameter validation
            Debug.Assert(htmlTbodyElement.LocalName.ToLower() == "tbody");
            Debug.Assert(columnStarts != null);

            double tbodyWidth = 0;
            bool columnWidthsAvailable = true;

            if(!htmlTbodyElement.HasChildNodes) {
                return tbodyWidth;
            }

            // Set active row spans to 0 - thus ignoring row spans crossing tbody boundaries
            ClearActiveRowSpans(activeRowSpans);

            XmlNode htmlChildNode = htmlTbodyElement.FirstChild;

            // Analyze tr elements
            while(htmlChildNode != null && columnWidthsAvailable) {
                switch(htmlChildNode.LocalName.ToLower()) {
                    case "tr":
                        double trWidth = AnalyzeTRStructure((XmlElement)htmlChildNode, columnStarts, activeRowSpans, tbodyWidth, stylesheet);
                        if(trWidth > tbodyWidth) {
                            tbodyWidth = trWidth;
                        }
                        break;
                    case "td":
                        columnWidthsAvailable = false; // interrupt the analisys
                        break;
                    default:
                        break;
                }
                htmlChildNode = htmlChildNode.NextSibling;
            }

            // Set active row spans to 0 - thus ignoring row spans crossing tbody boundaries
            ClearActiveRowSpans(activeRowSpans);

            return columnWidthsAvailable ? tbodyWidth : 0;
        }
        private static void AddSpanOrRun(XmlElement xamlParentElement, XmlElement htmlElement, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            // Decide what XAML element to use for this inline element.
            // Check whether it contains any nested inlines
            bool elementHasChildren = false;
            for(XmlNode htmlNode = htmlElement.FirstChild; htmlNode != null; htmlNode = htmlNode.NextSibling) {
                if(htmlNode is XmlElement) {
                    string htmlChildName = ((XmlElement)htmlNode).LocalName.ToLower();
                    if(HtmlSchema.IsInlineElement(htmlChildName) || HtmlSchema.IsBlockElement(htmlChildName) ||
                        htmlChildName == "img" || htmlChildName == "br" || htmlChildName == "hr") {
                        elementHasChildren = true;
                        break;
                    }
                }
            }

            string xamlElementName = elementHasChildren ? HtmlToXamlConverter.Xaml_Span : HtmlToXamlConverter.Xaml_Run;

            // Create currentProperties as a compilation of local and inheritedProperties, set localProperties
            Hashtable localProperties;
            Hashtable currentProperties = GetElementProperties(htmlElement, inheritedProperties, out localProperties, stylesheet, sourceContext);

            // Create a XAML element corresponding to this html element
            XmlElement xamlElement = xamlParentElement.OwnerDocument.CreateElement(/*prefix:*/null, /*localName:*/xamlElementName, _xamlNamespace);
            ApplyLocalProperties(xamlElement, localProperties, /*isBlock:*/false);

            // Recurse into element subtree
            for(XmlNode htmlChildNode = htmlElement.FirstChild; htmlChildNode != null; htmlChildNode = htmlChildNode.NextSibling) {
                AddInline(xamlElement, htmlChildNode, currentProperties, stylesheet, sourceContext);
            }

            // Add the new element to the parent.
            xamlParentElement.AppendChild(xamlElement);
        }
        /// <summary>
        /// Performs a parsing pass over a tr element to read information about column width and rowspan attributes.
        /// </summary>
        /// <param name="htmlTRElement">
        /// XmlElement representing Html tr element whose structure is to be analyzed
        /// </param>
        /// <param name="columnStarts">
        /// ArrayList of type double which contains the function output. If analysis is successful, this ArrayList contains
        /// all the points which are the starting position of any column in the tr, ordered from left to right. If analysis fails,
        /// the ArrayList is set to null
        /// </param>
        /// <param name="activeRowSpans">
        /// ArrayList representing all columns currently spanned by an earlier row span attribute. These columns should
        /// not be used for data in this row. The ArrayList actually contains notation for all columns in the table, if the
        /// active row span is set to 0 that column is not presently spanned but if it is > 0 the column is presently spanned
        /// </param>
        /// <param name="tableWidth">
        /// Double value representing the current width of the table.
        /// Return 0 if analisys was insuccessful.
        /// </param>
        private static double AnalyzeTRStructure(XmlElement htmlTRElement, ArrayList columnStarts, ArrayList activeRowSpans, double tableWidth, CssStylesheet stylesheet)
        {
            double columnWidth;

            // Parameter validation
            Debug.Assert(htmlTRElement.LocalName.ToLower() == "tr");
            Debug.Assert(columnStarts != null);
            Debug.Assert(activeRowSpans != null);
            Debug.Assert(columnStarts.Count == activeRowSpans.Count);

            if(!htmlTRElement.HasChildNodes) {
                return 0;
            }

            bool columnWidthsAvailable = true;

            double columnStart = 0; // starting position of current column
            XmlNode htmlChildNode = htmlTRElement.FirstChild;
            int columnIndex = 0;
            double trWidth = 0;

            // Skip spanned columns to get to real column start
            if(columnIndex < activeRowSpans.Count) {
                Debug.Assert((double)columnStarts[columnIndex] >= columnStart);
                if((double)columnStarts[columnIndex] == columnStart) {
                    // The new column may be in a spanned area
                    while(columnIndex < activeRowSpans.Count && (int)activeRowSpans[columnIndex] > 0) {
                        activeRowSpans[columnIndex] = (int)activeRowSpans[columnIndex] - 1;
                        Debug.Assert((int)activeRowSpans[columnIndex] >= 0);
                        columnIndex++;
                        columnStart = (double)columnStarts[columnIndex];
                    }
                }
            }

            while(htmlChildNode != null && columnWidthsAvailable) {
                Debug.Assert(columnStarts.Count == activeRowSpans.Count);

                VerifyColumnStartsAscendingOrder(columnStarts);

                switch(htmlChildNode.LocalName.ToLower()) {
                    case "td":
                        Debug.Assert(columnIndex <= columnStarts.Count);
                        if(columnIndex < columnStarts.Count) {
                            Debug.Assert(columnStart <= (double)columnStarts[columnIndex]);
                            if(columnStart < (double)columnStarts[columnIndex]) {
                                columnStarts.Insert(columnIndex, columnStart);
                                // There can be no row spans now - the column data will appear here
                                // Row spans may appear only during the column analysis
                                activeRowSpans.Insert(columnIndex, 0);
                            }
                        } else {
                            // Column start is greater than all previous starts. Row span must still be 0 because
                            // we are either adding after another column of the same row, in which case it should not inherit
                            // the previous column's span. Otherwise we are adding after the last column of some previous
                            // row, and assuming the table widths line up, we should not be spanned by it. If there is
                            // an incorrect tbale structure where a columns starts in the middle of a row span, we do not
                            // guarantee correct output
                            columnStarts.Add(columnStart);
                            activeRowSpans.Add(0);
                        }
                        columnWidth = GetColumnWidth((XmlElement)htmlChildNode);
                        if(columnWidth != -1) {
                            int nextColumnIndex;
                            int rowSpan = GetRowSpan((XmlElement)htmlChildNode);

                            nextColumnIndex = GetNextColumnIndex(columnIndex, columnWidth, columnStarts, activeRowSpans);
                            if(nextColumnIndex != -1) {
                                // Entire column width can be processed without hitting conflicting row span. This means that
                                // column widths line up and we can process them
                                Debug.Assert(nextColumnIndex <= columnStarts.Count);

                                // Apply row span to affected columns
                                for(int spannedColumnIndex = columnIndex; spannedColumnIndex < nextColumnIndex; spannedColumnIndex++) {
                                    activeRowSpans[spannedColumnIndex] = rowSpan - 1;
                                    Debug.Assert((int)activeRowSpans[spannedColumnIndex] >= 0);
                                }

                                columnIndex = nextColumnIndex;

                                // Calculate columnsStart for the next cell
                                columnStart = columnStart + columnWidth;

                                if(columnIndex < activeRowSpans.Count) {
                                    Debug.Assert((double)columnStarts[columnIndex] >= columnStart);
                                    if((double)columnStarts[columnIndex] == columnStart) {
                                        // The new column may be in a spanned area
                                        while(columnIndex < activeRowSpans.Count && (int)activeRowSpans[columnIndex] > 0) {
                                            activeRowSpans[columnIndex] = (int)activeRowSpans[columnIndex] - 1;
                                            Debug.Assert((int)activeRowSpans[columnIndex] >= 0);
                                            columnIndex++;
                                            columnStart = (double)columnStarts[columnIndex];
                                        }
                                    }
                                    // else: the new column does not start at the same time as a pre existing column
                                    // so we don't have to check it for active row spans, it starts in the middle
                                    // of another column which has been checked already by the GetNextColumnIndex function
                                }
                            } else {
                                // Full column width cannot be processed without a pre existing row span.
                                // We cannot analyze widths
                                columnWidthsAvailable = false;
                            }
                        } else {
                            // Incorrect column width, stop processing
                            columnWidthsAvailable = false;
                        }
                        break;
                    default:
                        break;
                }

                htmlChildNode = htmlChildNode.NextSibling;
            }

            // The width of the tr element is the position at which it's last td element ends, which is calculated in
            // the columnStart value after each td element is processed
            if(columnWidthsAvailable) {
                trWidth = columnStart;
            } else {
                trWidth = 0;
            }

            return trWidth;
        }
        // .............................................................
        //
        // Tables
        //
        // .............................................................
        /// <summary>
        /// Converts htmlTableElement to a Xaml Table element. Adds tbody elements if they are missing so
        /// that a resulting Xaml Table element is properly formed.
        /// </summary>
        /// <param name="xamlParentElement">
        /// Parent xaml element to which a converted table must be added.
        /// </param>
        /// <param name="htmlTableElement">
        /// XmlElement reprsenting the Html table element to be converted
        /// </param>
        /// <param name="inheritedProperties">
        /// Hashtable representing properties inherited from parent context.
        /// </param>
        private static void AddTable(XmlElement xamlParentElement, XmlElement htmlTableElement, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            // Parameter validation
            Debug.Assert(htmlTableElement.LocalName.ToLower() == "table");
            Debug.Assert(xamlParentElement != null);
            Debug.Assert(inheritedProperties != null);

            // Create current properties to be used by children as inherited properties, set local properties
            Hashtable localProperties;
            Hashtable currentProperties = GetElementProperties(htmlTableElement, inheritedProperties, out localProperties, stylesheet, sourceContext);

            // TODO: process localProperties for tables to override defaults, decide cell spacing defaults

            // Check if the table contains only one cell - we want to take only its content
            XmlElement singleCell = GetCellFromSingleCellTable(htmlTableElement);

            if(singleCell != null) {
                //  Need to push skipped table elements onto sourceContext
                sourceContext.Add(singleCell);

                // Add the cell's content directly to parent
                for(XmlNode htmlChildNode = singleCell.FirstChild; htmlChildNode != null; htmlChildNode = htmlChildNode != null ? htmlChildNode.NextSibling : null) {
                    htmlChildNode = AddBlock(xamlParentElement, htmlChildNode, currentProperties, stylesheet, sourceContext);
                }

                Debug.Assert(sourceContext.Count > 0 && sourceContext[sourceContext.Count - 1] == singleCell);
                sourceContext.RemoveAt(sourceContext.Count - 1);
            } else {
                // Create xamlTableElement
                XmlElement xamlTableElement = xamlParentElement.OwnerDocument.CreateElement(null, Xaml_Table, _xamlNamespace);

                // Analyze table structure for column widths and rowspan attributes
                ArrayList columnStarts = AnalyzeTableStructure(htmlTableElement, stylesheet);

                // Process COLGROUP & COL elements
                AddColumnInformation(htmlTableElement, xamlTableElement, columnStarts, currentProperties, stylesheet, sourceContext);

                // Process table body - TBODY and TR elements
                XmlNode htmlChildNode = htmlTableElement.FirstChild;

                while(htmlChildNode != null) {
                    string htmlChildName = htmlChildNode.LocalName.ToLower();

                    // Process the element
                    if(htmlChildName == "tbody" || htmlChildName == "thead" || htmlChildName == "tfoot") {
                        //  Add more special processing for TableHeader and TableFooter
                        XmlElement xamlTableBodyElement = xamlTableElement.OwnerDocument.CreateElement(null, Xaml_TableRowGroup, _xamlNamespace);
                        xamlTableElement.AppendChild(xamlTableBodyElement);

                        sourceContext.Add((XmlElement)htmlChildNode);

                        // Get properties of Html tbody element
                        Hashtable tbodyElementLocalProperties;
                        Hashtable tbodyElementCurrentProperties = GetElementProperties((XmlElement)htmlChildNode, currentProperties, out tbodyElementLocalProperties, stylesheet, sourceContext);
                        // TODO: apply local properties for tbody

                        // Process children of htmlChildNode, which is tbody, for tr elements
                        AddTableRowsToTableBody(xamlTableBodyElement, htmlChildNode.FirstChild, tbodyElementCurrentProperties, columnStarts, stylesheet, sourceContext);
                        if(xamlTableBodyElement.HasChildNodes) {
                            xamlTableElement.AppendChild(xamlTableBodyElement);
                            // else: if there is no TRs in this TBody, we simply ignore it
                        }

                        Debug.Assert(sourceContext.Count > 0 && sourceContext[sourceContext.Count - 1] == htmlChildNode);
                        sourceContext.RemoveAt(sourceContext.Count - 1);

                        htmlChildNode = htmlChildNode.NextSibling;
                    } else if(htmlChildName == "tr") {
                        // Tbody is not present, but tr element is present. Tr is wrapped in tbody
                        XmlElement xamlTableBodyElement = xamlTableElement.OwnerDocument.CreateElement(null, Xaml_TableRowGroup, _xamlNamespace);

                        // We use currentProperties of xamlTableElement when adding rows since the tbody element is artificially created and has
                        // no properties of its own

                        htmlChildNode = AddTableRowsToTableBody(xamlTableBodyElement, htmlChildNode, currentProperties, columnStarts, stylesheet, sourceContext);
                        if(xamlTableBodyElement.HasChildNodes) {
                            xamlTableElement.AppendChild(xamlTableBodyElement);
                        }
                    } else {
                        // Element is not tbody or tr. Ignore it.
                        // TODO: add processing for thead, tfoot elements and recovery for td elements
                        htmlChildNode = htmlChildNode.NextSibling;
                    }
                }

                if(xamlTableElement.HasChildNodes) {
                    xamlParentElement.AppendChild(xamlTableElement);
                }
            }
        }
        // .................................................................
        //
        // Processing CSS Attributes
        //
        // .................................................................
        internal static void GetElementPropertiesFromCssAttributes(XmlElement htmlElement, string elementName, CssStylesheet stylesheet, Hashtable localProperties, List<XmlElement> sourceContext)
        {
            string styleFromStylesheet = stylesheet.GetStyle(elementName, sourceContext);

            string styleInline = HtmlToXamlConverter.GetAttribute(htmlElement, "style");

            // Combine styles from stylesheet and from inline attribute.
            // The order is important - the latter styles will override the former.
            string style = styleFromStylesheet != null ? styleFromStylesheet : null;
            if(styleInline != null) {
                style = style == null ? styleInline : (style + ";" + styleInline);
            }

            // Apply local style to current formatting properties
            if(style != null) {
                string[] styleValues = style.Split(';');
                for(int i = 0; i < styleValues.Length; i++) {
                    string[] styleNameValue;

                    styleNameValue = styleValues[i].Split(':');
                    if(styleNameValue.Length == 2) {
                        string styleName = styleNameValue[0].Trim().ToLower();
                        string styleValue = HtmlToXamlConverter.UnQuote(styleNameValue[1].Trim()).ToLower();
                        int nextIndex = 0;

                        switch(styleName) {
                            case "font":
                                ParseCssFont(styleValue, localProperties);
                                break;
                            case "font-family":
                                ParseCssFontFamily(styleValue, ref nextIndex, localProperties);
                                break;
                            case "font-size":
                                ParseCssSize(styleValue, ref nextIndex, localProperties, "font-size", /*mustBeNonNegative:*/true);
                                break;
                            case "font-style":
                                ParseCssFontStyle(styleValue, ref nextIndex, localProperties);
                                break;
                            case "font-weight":
                                ParseCssFontWeight(styleValue, ref nextIndex, localProperties);
                                break;
                            case "font-variant":
                                ParseCssFontVariant(styleValue, ref nextIndex, localProperties);
                                break;
                            case "line-height":
                                ParseCssSize(styleValue, ref nextIndex, localProperties, "line-height", /*mustBeNonNegative:*/true);
                                break;
                            case "word-spacing":
                                //  Implement word-spacing conversion
                                break;
                            case "letter-spacing":
                                //  Implement letter-spacing conversion
                                break;
                            case "color":
                                ParseCssColor(styleValue, ref nextIndex, localProperties, "color");
                                break;

                            case "text-decoration":
                                ParseCssTextDecoration(styleValue, ref nextIndex, localProperties);
                                break;

                            case "text-transform":
                                ParseCssTextTransform(styleValue, ref nextIndex, localProperties);
                                break;

                            case "background-color":
                                ParseCssColor(styleValue, ref nextIndex, localProperties, "background-color");
                                break;
                            case "background":
                                // TODO: need to parse composite background property
                                ParseCssBackground(styleValue, ref nextIndex, localProperties);
                                break;

                            case "text-align":
                                ParseCssTextAlign(styleValue, ref nextIndex, localProperties);
                                break;
                            case "vertical-align":
                                ParseCssVerticalAlign(styleValue, ref nextIndex, localProperties);
                                break;
                            case "text-indent":
                                ParseCssSize(styleValue, ref nextIndex, localProperties, "text-indent", /*mustBeNonNegative:*/false);
                                break;

                            case "width":
                            case "height":
                                ParseCssSize(styleValue, ref nextIndex, localProperties, styleName, /*mustBeNonNegative:*/true);
                                break;

                            case "margin": // top/right/bottom/left
                                ParseCssRectangleProperty(styleValue, ref nextIndex, localProperties, styleName);
                                break;
                            case "margin-top":
                            case "margin-right":
                            case "margin-bottom":
                            case "margin-left":
                                ParseCssSize(styleValue, ref nextIndex, localProperties, styleName, /*mustBeNonNegative:*/true);
                                break;

                            case "padding":
                                ParseCssRectangleProperty(styleValue, ref nextIndex, localProperties, styleName);
                                break;
                            case "padding-top":
                            case "padding-right":
                            case "padding-bottom":
                            case "padding-left":
                                ParseCssSize(styleValue, ref nextIndex, localProperties, styleName, /*mustBeNonNegative:*/true);
                                break;

                            case "border":
                                ParseCssBorder(styleValue, ref nextIndex, localProperties);
                                break;
                            case "border-style":
                            case "border-width":
                            case "border-color":
                                ParseCssRectangleProperty(styleValue, ref nextIndex, localProperties, styleName);
                                break;
                            case "border-top":
                            case "border-right":
                            case "border-left":
                            case "border-bottom":
                                //  Parse css border style
                                break;

                            // NOTE: css names for elementary border styles have side indications in the middle (top/bottom/left/right)
                            // In our internal notation we intentionally put them at the end - to unify processing in ParseCssRectangleProperty method
                            case "border-top-style":
                            case "border-right-style":
                            case "border-left-style":
                            case "border-bottom-style":
                            case "border-top-color":
                            case "border-right-color":
                            case "border-left-color":
                            case "border-bottom-color":
                            case "border-top-width":
                            case "border-right-width":
                            case "border-left-width":
                            case "border-bottom-width":
                                //  Parse css border style
                                break;

                            case "display":
                                //  Implement display style conversion
                                break;

                            case "float":
                                ParseCssFloat(styleValue, ref nextIndex, localProperties);
                                break;
                            case "clear":
                                ParseCssClear(styleValue, ref nextIndex, localProperties);
                                break;

                            default:
                                break;
                        }
                    }
                }
            }
        }
        /// <summary>
        /// Adds TableCell elements to xamlTableRowElement.
        /// </summary>
        /// <param name="xamlTableRowElement">
        /// XmlElement representing Xaml TableRow element to which the converted cells should be added
        /// </param>
        /// <param name="htmlTDStartNode">
        /// XmlElement representing the child of tr or tbody element from which we should start adding td elements
        /// </param>
        /// <param name="currentProperties">
        /// properties of the current html tr element to which cells are to be added
        /// </param>
        /// <returns>
        /// XmlElement representing the current position of the iterator among the children of the parent Html tbody/tr element
        /// </returns>
        private static XmlNode AddTableCellsToTableRow(XmlElement xamlTableRowElement, XmlNode htmlTDStartNode, Hashtable currentProperties, ArrayList columnStarts, ArrayList activeRowSpans, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            // parameter validation
            Debug.Assert(xamlTableRowElement.LocalName == Xaml_TableRow);
            Debug.Assert(currentProperties != null);
            if(columnStarts != null) {
                Debug.Assert(activeRowSpans.Count == columnStarts.Count);
            }

            XmlNode htmlChildNode = htmlTDStartNode;
            double columnStart = 0;
            double columnWidth = 0;
            int columnIndex = 0;
            int columnSpan = 0;

            while(htmlChildNode != null && htmlChildNode.LocalName.ToLower() != "tr" && htmlChildNode.LocalName.ToLower() != "tbody" && htmlChildNode.LocalName.ToLower() != "thead" && htmlChildNode.LocalName.ToLower() != "tfoot") {
                if(htmlChildNode.LocalName.ToLower() == "td" || htmlChildNode.LocalName.ToLower() == "th") {
                    XmlElement xamlTableCellElement = xamlTableRowElement.OwnerDocument.CreateElement(null, Xaml_TableCell, _xamlNamespace);

                    sourceContext.Add((XmlElement)htmlChildNode);

                    Hashtable tdElementLocalProperties;
                    Hashtable tdElementCurrentProperties = GetElementProperties((XmlElement)htmlChildNode, currentProperties, out tdElementLocalProperties, stylesheet, sourceContext);

                    // TODO: determine if localProperties can be used instead of htmlChildNode in this call, and if they can,
                    // make necessary changes and use them instead.
                    ApplyPropertiesToTableCellElement((XmlElement)htmlChildNode, xamlTableCellElement);

                    if(columnStarts != null) {
                        Debug.Assert(columnIndex < columnStarts.Count - 1);
                        while(columnIndex < activeRowSpans.Count && (int)activeRowSpans[columnIndex] > 0) {
                            activeRowSpans[columnIndex] = (int)activeRowSpans[columnIndex] - 1;
                            Debug.Assert((int)activeRowSpans[columnIndex] >= 0);
                            columnIndex++;
                        }
                        Debug.Assert(columnIndex < columnStarts.Count - 1);
                        columnStart = (double)columnStarts[columnIndex];
                        columnWidth = GetColumnWidth((XmlElement)htmlChildNode);
                        columnSpan = CalculateColumnSpan(columnIndex, columnWidth, columnStarts);
                        int rowSpan = GetRowSpan((XmlElement)htmlChildNode);

                        // Column cannot have no span
                        Debug.Assert(columnSpan > 0);
                        Debug.Assert(columnIndex + columnSpan < columnStarts.Count);

                        xamlTableCellElement.SetAttribute(Xaml_TableCell_ColumnSpan, columnSpan.ToString());

                        // Apply row span
                        for(int spannedColumnIndex = columnIndex; spannedColumnIndex < columnIndex + columnSpan; spannedColumnIndex++) {
                            Debug.Assert(spannedColumnIndex < activeRowSpans.Count);
                            activeRowSpans[spannedColumnIndex] = (rowSpan - 1);
                            Debug.Assert((int)activeRowSpans[spannedColumnIndex] >= 0);
                        }

                        columnIndex = columnIndex + columnSpan;
                    }

                    AddDataToTableCell(xamlTableCellElement, htmlChildNode.FirstChild, tdElementCurrentProperties, stylesheet, sourceContext);
                    if(xamlTableCellElement.HasChildNodes) {
                        xamlTableRowElement.AppendChild(xamlTableCellElement);
                    }

                    Debug.Assert(sourceContext.Count > 0 && sourceContext[sourceContext.Count - 1] == htmlChildNode);
                    sourceContext.RemoveAt(sourceContext.Count - 1);

                    htmlChildNode = htmlChildNode.NextSibling;
                } else {
                    // Not td element. Ignore it.
                    // TODO: Consider better recovery
                    htmlChildNode = htmlChildNode.NextSibling;
                }
            }
            return htmlChildNode;
        }
        /// <summary>
        /// Analyzes the given htmlElement expecting it to be converted
        /// into some of xaml Block elements and adds the converted block
        /// to the children collection of xamlParentElement.
        ///
        /// Analyzes the given XmlElement htmlElement, recognizes it as some HTML element
        /// and adds it as a child to a xamlParentElement.
        /// In some cases several following siblings of the given htmlElement
        /// will be consumed too (e.g. LIs encountered without wrapping UL/OL,
        /// which must be collected together and wrapped into one implicit List element).
        /// </summary>
        /// <param name="xamlParentElement">
        /// Parent xaml element, to which new converted element will be added
        /// </param>
        /// <param name="htmlElement">
        /// Source html element subject to convert to xaml.
        /// </param>
        /// <param name="inheritedProperties">
        /// Properties inherited from an outer context.
        /// </param>
        /// <param name="stylesheet"></param>
        /// <param name="sourceContext"></param>
        /// <returns>
        /// Last processed html node. Normally it should be the same htmlElement
        /// as was passed as a paramater, but in some irregular cases
        /// it could one of its following siblings.
        /// The caller must use this node to get to next sibling from it.
        /// </returns>
        private static XmlNode AddBlock(XmlElement xamlParentElement, XmlNode htmlNode, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            if(htmlNode is XmlComment) {
                DefineInlineFragmentParent((XmlComment)htmlNode, /*xamlParentElement:*/null);
            } else if(htmlNode is XmlText) {
                htmlNode = AddImplicitParagraph(xamlParentElement, htmlNode, inheritedProperties, stylesheet, sourceContext);
            } else if(htmlNode is XmlElement) {
                // Identify element name
                XmlElement htmlElement = (XmlElement)htmlNode;

                string htmlElementName = htmlElement.LocalName; // Keep the name case-sensitive to check xml names
                string htmlElementNamespace = htmlElement.NamespaceURI;

                if(htmlElementNamespace != HtmlParser.XhtmlNamespace) {
                    // Non-html element. skip it
                    // Isn't it too agressive? What if this is just an error in html tag name?
                    // TODO: Consider skipping just a wparrer in recursing into the element tree,
                    // which may produce some garbage though coming from xml fragments.
                    return htmlElement;
                }

                // Put source element to the stack
                sourceContext.Add(htmlElement);

                // Convert the name to lowercase, because html elements are case-insensitive
                htmlElementName = htmlElementName.ToLower();

                // Switch to an appropriate kind of processing depending on html element name
                switch(htmlElementName) {
                    // Sections:
                    case "html":
                    case "body":
                    case "div":
                    case "form": // not a block according to xhtml spec
                    case "pre": // Renders text in a fixed-width font
                    case "blockquote":
                    case "caption":
                    case "center":
                    case "cite":
                        AddSection(xamlParentElement, htmlElement, inheritedProperties, stylesheet, sourceContext);
                        break;

                    // Paragraphs:
                    case "p":
                    case "h1":
                    case "h2":
                    case "h3":
                    case "h4":
                    case "h5":
                    case "h6":
                    case "nsrtitle":
                    case "textarea":
                    case "dd": // ???
                    case "dl": // ???
                    case "dt": // ???
                    case "tt": // ???
                        AddParagraph(xamlParentElement, htmlElement, inheritedProperties, stylesheet, sourceContext);
                        break;

                    case "ol":
                    case "ul":
                    case "dir": //  treat as UL element
                    case "menu": //  treat as UL element
                        // List element conversion
                        AddList(xamlParentElement, htmlElement, inheritedProperties, stylesheet, sourceContext);
                        break;
                    case "li":
                        // LI outside of OL/UL
                        // Collect all sibling LIs, wrap them into a List and then proceed with the element following the last of LIs
                        htmlNode = AddOrphanListItems(xamlParentElement, htmlElement, inheritedProperties, stylesheet, sourceContext);
                        break;

                    case "img":
                        // TODO: Add image processing
                        AddImage(xamlParentElement, htmlElement, inheritedProperties, stylesheet, sourceContext);
                        break;

                    case "table":
                        // hand off to table parsing function which will perform special table syntax checks
                        AddTable(xamlParentElement, htmlElement, inheritedProperties, stylesheet, sourceContext);
                        break;

                    case "tbody":
                    case "tfoot":
                    case "thead":
                    case "tr":
                    case "td":
                    case "th":
                        // Table stuff without table wrapper
                        // TODO: add special-case processing here for elements that should be within tables when the
                        // parent element is NOT a table. If the parent element is a table they can be processed normally.
                        // we need to compare against the parent element here, we can't just break on a switch
                        goto default; // Thus we will skip this element as unknown, but still recurse into it.

                    case "style": // We already pre-processed all style elements. Ignore it now
                    case "meta":
                    case "head":
                    case "title":
                    case "script":
                        // Ignore these elements
                        break;

                    default:
                        // Wrap a sequence of inlines into an implicit paragraph
                        htmlNode = AddImplicitParagraph(xamlParentElement, htmlElement, inheritedProperties, stylesheet, sourceContext);
                        break;
                }

                // Remove the element from the stack
                Debug.Assert(sourceContext.Count > 0 && sourceContext[sourceContext.Count - 1] == htmlElement);
                sourceContext.RemoveAt(sourceContext.Count - 1);
            }

            // Return last processed node
            return htmlNode;
        }
        /// <summary>
        /// Converts htmlColElement into Xaml TableColumn element, and appends it to the parent
        /// xamlTableColumnGroupElement
        /// </summary>
        /// <param name="xamlTableElement"></param>
        /// <param name="htmlColElement">
        /// XmlElement representing Html col element to be converted
        /// </param>
        /// <param name="inheritedProperties">
        /// properties inherited from parent context
        /// </param>
        /// <param name="stylesheet"></param>
        /// <param name="sourceContext"></param>
        private static void AddTableColumn(XmlElement xamlTableElement, XmlElement htmlColElement, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            Hashtable localProperties;
            Hashtable currentProperties = GetElementProperties(htmlColElement, inheritedProperties, out localProperties, stylesheet, sourceContext);

            XmlElement xamlTableColumnElement = xamlTableElement.OwnerDocument.CreateElement(null, Xaml_TableColumn, _xamlNamespace);

            // TODO: process local properties for TableColumn element

            // Col is an empty element, with no subtree
            xamlTableElement.AppendChild(xamlTableColumnElement);
        }
        /// <summary>
        /// adds table cell data to xamlTableCellElement
        /// </summary>
        /// <param name="xamlTableCellElement">
        /// XmlElement representing Xaml TableCell element to which the converted data should be added
        /// </param>
        /// <param name="htmlDataStartNode">
        /// XmlElement representing the start element of data to be added to xamlTableCellElement
        /// </param>
        /// <param name="currentProperties">
        /// Current properties for the html td/th element corresponding to xamlTableCellElement
        /// </param>
        private static void AddDataToTableCell(XmlElement xamlTableCellElement, XmlNode htmlDataStartNode, Hashtable currentProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            // Parameter validation
            Debug.Assert(xamlTableCellElement.LocalName == Xaml_TableCell);
            Debug.Assert(currentProperties != null);

            for(XmlNode htmlChildNode = htmlDataStartNode; htmlChildNode != null; htmlChildNode = htmlChildNode != null ? htmlChildNode.NextSibling : null) {
                // Process a new html element and add it to the td element
                htmlChildNode = AddBlock(xamlTableCellElement, htmlChildNode, currentProperties, stylesheet, sourceContext);
            }
        }
        /// <summary>
        /// Converts htmlColgroupElement into Xaml TableColumnGroup element, and appends it to the parent
        /// xamlTableElement
        /// </summary>
        /// <param name="xamlTableElement">
        /// XmlElement representing Xaml Table element to which the converted column group should be added
        /// </param>
        /// <param name="htmlColgroupElement">
        /// XmlElement representing Html colgroup element to be converted
        /// <param name="inheritedProperties">
        /// Properties inherited from parent context
        /// </param>
        private static void AddTableColumnGroup(XmlElement xamlTableElement, XmlElement htmlColgroupElement, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            Hashtable localProperties;
            Hashtable currentProperties = GetElementProperties(htmlColgroupElement, inheritedProperties, out localProperties, stylesheet, sourceContext);

            // TODO: process local properties for colgroup

            // Process children of colgroup. Colgroup may contain only col elements.
            for(XmlNode htmlNode = htmlColgroupElement.FirstChild; htmlNode != null; htmlNode = htmlNode.NextSibling) {
                if(htmlNode is XmlElement && htmlNode.LocalName.ToLower() == "col") {
                    AddTableColumn(xamlTableElement, (XmlElement)htmlNode, currentProperties, stylesheet, sourceContext);
                }
            }
        }
 // .............................................................
 //
 // Images
 //
 // .............................................................
 private static void AddImage(XmlElement xamlParentElement, XmlElement htmlElement, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
 {
     //  Implement images
 }
        private static void AddImage(XmlElement xamlParentElement, XmlElement htmlElement, Hashtable inheritedProperties, CssStylesheet stylesheet, List<XmlElement> sourceContext)
        {
            // Create currentProperties as a compilation of local and inheritedProperties, set localProperties
            Hashtable localProperties;
            Hashtable currentProperties = GetElementProperties(htmlElement, inheritedProperties, out localProperties, stylesheet, sourceContext);

            // Create a XAML element corresponding to this html element
            XmlElement xamlElement = xamlParentElement.OwnerDocument.CreateElement(/*prefix:*/null, /*localName:*/Xaml_Image, _xamlNamespace);
            ApplyLocalProperties(xamlElement, localProperties, /*isBlock:*/false);

            if(!xamlElement.HasAttribute(Xaml_MaxHeight) && !xamlElement.HasAttribute(Xaml_MaxWidth)) {
                xamlElement.SetAttribute("Stretch", BlockContainers.Contains(xamlParentElement.Name) ? "UniformToFill" : "None");
            }

            XmlElement container = xamlParentElement.OwnerDocument.CreateElement(
                null,
                BlockContainers.Contains(xamlParentElement.Name) ? "BlockUIContainer" : "InlineUIContainer",
                _xamlNamespace);
            container.AppendChild(xamlElement);

            xamlParentElement.AppendChild(container);
        }