/// <summary>
        /// Executes the paste operation on the given element.
        /// </summary>
        /// <param name="modelElement">Element.</param>
        /// <returns>Validation result, indicating problems during the paste operation.</returns>
        public static ValidationResult ExecutePaste(ModelElement modelElement)
        {
            System.Windows.IDataObject idataObject = System.Windows.Clipboard.GetDataObject();

            ValidationResult result = null;

            using (Transaction transaction = modelElement.Store.TransactionManager.BeginTransaction("Paste", true))
            {
                result = ModelElementOperations.Merge(modelElement, idataObject);

                List <Guid> shapes = DiagramsShapeStore.GetFromStore(modelElement.Id);
                if (shapes != null)
                {
                    foreach (Guid s in shapes)
                    {
                        NodeShape shape = modelElement.Store.ElementDirectory.FindElement(s) as NodeShape;
                        if (shape != null)
                        {
                            using (Transaction tShape = modelElement.Store.TransactionManager.BeginTransaction("Create shape", true))
                            {
                                shape.FixUpMissingShapes();
                                tShape.Commit();
                            }
                            using (Transaction tLinkShapes = modelElement.Store.TransactionManager.BeginTransaction("Fixup missing link shapes", true))
                            {
                                shape.FixUpMissingLinkShapes();
                                tLinkShapes.Commit();
                            }
                        }
                    }
                }
                transaction.Commit();
            }

            ModelProtoGroup group = ModelElementOperations.GetModelProtoGroup(idataObject);

            if (group != null)
            {
                if (group.Operation == ModelProtoGroupOperation.Move)
                {
                    System.Windows.Clipboard.Clear();
                    ElementsInMoveMode.Clear();
                }
            }

            return(result);
        }
        /// <summary>
        /// Helper method of the cut opeation.
        /// </summary>
        /// <param name="eventManager">Event manager.</param>
        /// <param name="idataObject">Data object.</param>
        public static void ProcessMoveMode(ViewModelEventManager eventManager, System.Windows.IDataObject idataObject)
        {
            bool isInMoveMode = false;

            if (idataObject != null)
            {
                ModelProtoGroup group = ModelElementOperations.GetModelProtoGroup(idataObject);
                if (group != null)
                {
                    if (group.Operation == ModelProtoGroupOperation.Move)
                    {
                        isInMoveMode = true;

                        List <System.Guid> guids = new List <System.Guid>();
                        foreach (ModelProtoElement root in group.ProtoRootElements)
                        {
                            guids.Add(root.ElementId);
                        }
                        foreach (System.Guid id in guids)
                        {
                            if (!ElementsInMoveMode.Contains(id))
                            {
                                eventManager.GetEvent <ModelElementCustomEvent <bool> >().Publish(true, ModelElementCustomEventNames.ModelElementMoveModeStatus, id);
                                ElementsInMoveMode.Add(id);
                            }
                        }
                        for (int i = ElementsInMoveMode.Count - 1; i >= 0; i--)
                        {
                            if (!guids.Contains(ElementsInMoveMode[i]))
                            {
                                eventManager.GetEvent <ModelElementCustomEvent <bool> >().Publish(false, ModelElementCustomEventNames.ModelElementMoveModeStatus, ElementsInMoveMode[i]);
                                ElementsInMoveMode.RemoveAt(i);
                            }
                        }
                    }
                }
            }

            if (!isInMoveMode)
            {
                // remove all elements from the current list and notify them to change status
                foreach (System.Guid id in ElementsInMoveMode)
                {
                    eventManager.GetEvent <ModelElementCustomEvent <bool> >().Publish(false, ModelElementCustomEventNames.ModelElementMoveModeStatus, id);
                }
            }
        }