private void btnHighlightAll_Click(object sender, EventArgs e)
        {
            if (!_highlightGroups.ContainsKey(_editor))
                _highlightGroups[_editor] = new HighlightGroup(_editor);
            HighlightGroup group = _highlightGroups[_editor];

            if (string.IsNullOrEmpty(LookFor))
                // Clear highlights
                group.ClearMarkers();
            else {
                _search.LookFor = txtLookFor.Text;
                _search.MatchCase = chkMatchCase.Checked;
                _search.MatchWholeWordOnly = chkMatchWholeWord.Checked;

                bool looped = false;
                int offset = 0, count = 0;
                for(;;) {
                    TextRange range = _search.FindNext(offset, false, out looped);
                    if (range == null || looped)
                        break;
                    offset = range.Offset + range.Length;
                    count++;

                    var m = new TextMarker(range.Offset, range.Length,
                            TextMarkerType.SolidBlock, Color.Yellow, Color.Black);
                    group.AddMarker(m);
                }
                if (count == 0)
                    MessageBox.Show("Search text not found.");
                else
                    Close();
            }
        }
        private void highlightSelectionToolStripMenuItem_Click(object sender, EventArgs e)
        {
            string LookFor = string.Empty;

            LookFor = editor.ActiveTextAreaControl.TextArea.SelectionManager.SelectedText;

            // if there's text selected, highlight all!
            if (!_highlightGroups.ContainsKey(editor))
                _highlightGroups[editor] = new HighlightGroup(editor);
            HighlightGroup group = _highlightGroups[editor];
            TextEditorSearcher _search = new TextEditorSearcher();
            _search.Document = editor.Document;

            group.ClearMarkers();

            _search.LookFor = LookFor;
            _search.MatchCase = true;
            _search.MatchWholeWordOnly = true;

            bool looped = false;
            int offset = 0, count = 0;
            for (; ; )
            {
                TextRange range = _search.FindNext(offset, false, out looped);
                if (range == null || looped)
                    break;
                offset = range.Offset + range.Length;
                count++;

                var m = new TextMarker(range.Offset, range.Length,
                        TextMarkerType.SolidBlock, Color.Orange, Color.Black);
                group.AddMarker(m);
            }

            editor.Invalidate();
            editor.Refresh();
        }