Fixed commenting out lines selected from the line number margin.

src/AddIns/BackendBindings/CSharpBinding/Project/Src/FormattingStrategy/CSharpFormattingStrategy.cs

@@ -313,7 +313,7 @@ namespace CSharpBinding.FormattingStrategy
 				case '>':
 					if (IsInsideDocumentationComment(textArea, curLine, cursorOffset)) {
 						curLineText = curLine.Text;
-						int column = textArea.Caret.Offset - curLine.Offset;
+						int column = cursorOffset - curLine.Offset;
 						int index = Math.Min(column - 1, curLineText.Length - 1);
 						
 						while (index >= 0 && curLineText[index] != '<') {
@@ -332,9 +332,7 @@ namespace CSharpBinding.FormattingStrategy
 								tag += ">";
 							}
 							if (!tag.StartsWith("/")) {
-								int caretOffset = textArea.Caret.Offset;
-								textArea.Document.Insert(caretOffset, "</" + tag.Substring(1));
-								textArea.Caret.Offset = caretOffset;
+								textArea.Document.Insert(cursorOffset, "</" + tag.Substring(1), AnchorMovementType.BeforeInsertion);
 							}
 						}
 					}

src/Main/Base/Project/Src/Editor/AvalonEdit/AvalonEditDocumentAdapter.cs

@@ -145,6 +145,15 @@ namespace ICSharpCode.SharpDevelop.Editor.AvalonEdit
 			document.Insert(offset, text);
 		}
 		
+		public void Insert(int offset, string text, AnchorMovementType defaultAnchorMovementType)
+		{
+			if (defaultAnchorMovementType == AnchorMovementType.BeforeInsertion) {
+				document.Replace(offset, 0, text, OffsetChangeMappingType.KeepAnchorBeforeInsertion);
+			} else {
+				document.Insert(offset, text);
+			}
+		}
+		
 		public void Remove(int offset, int length)
 		{
 			document.Remove(offset, length);
@@ -155,6 +164,11 @@ namespace ICSharpCode.SharpDevelop.Editor.AvalonEdit
 			document.Replace(offset, length, newText);
 		}
 		
+		public void Replace(int offset, int length, string newText, AnchorMovementType defaultAnchorMovementType)
+		{
+			document.Replace(offset, length, newText);
+		}
+		
 		public char GetCharAt(int offset)
 		{
 			return document.GetCharAt(offset);

src/Main/Base/Project/Src/Editor/IDocument.cs

@@ -38,6 +38,7 @@ namespace ICSharpCode.SharpDevelop.Editor
 		Location OffsetToPosition(int offset);
 		
 		void Insert(int offset, string text);
+		void Insert(int offset, string text, AnchorMovementType defaultAnchorMovementType);
 		void Remove(int offset, int length);
 		void Replace(int offset, int length, string newText);
 		

src/Main/Base/Project/Src/Editor/IFormattingStrategy.cs

@@ -76,20 +76,23 @@ namespace ICSharpCode.SharpDevelop.Editor
 				Location startPosition = editor.Document.OffsetToPosition(editor.SelectionStart);
 				Location endPosition = editor.Document.OffsetToPosition(editor.SelectionStart + editor.SelectionLength);
 				
+				// endLine is one above endPosition if no characters are selected on the last line (e.g. line selection from the margin)
+				int endLine = (endPosition.Column == 1 && endPosition.Line > startPosition.Line) ? endPosition.Line - 1 : endPosition.Line;
+				
 				List<IDocumentLine> lines = new List<IDocumentLine>();
 				bool removeComment = true;
 				
-				for (int i = startPosition.Line; i <= endPosition.Line; i++) {
+				for (int i = startPosition.Line; i <= endLine; i++) {
 					lines.Add(editor.Document.GetLine(i));
-					if (!lines[i - startPosition.Line].Text.Trim().StartsWith(comment))
+					if (!lines[i - startPosition.Line].Text.Trim().StartsWith(comment, StringComparison.Ordinal))
 						removeComment = false;
 				}
 				
 				foreach (IDocumentLine line in lines) {
 					if (removeComment) {
-						editor.Document.Remove(line.Offset + line.Text.IndexOf(comment), comment.Length);
+						editor.Document.Remove(line.Offset + line.Text.IndexOf(comment, StringComparison.Ordinal), comment.Length);
 					} else {
-						editor.Document.Insert(line.Offset, comment);
+						editor.Document.Insert(line.Offset, comment, AnchorMovementType.BeforeInsertion);
 					}
 				}
 			}

src/Main/Base/Project/Src/Editor/ReadOnlyDocument.cs

@@ -18,6 +18,8 @@ namespace ICSharpCode.SharpDevelop.Editor
 		
 		public ReadOnlyDocument(ITextBuffer textBuffer)
 		{
+			if (textBuffer == null)
+				throw new ArgumentNullException("textBuffer");
 			// ensure that underlying buffer is immutable
 			this.textBuffer = textBuffer.CreateSnapshot();
 			List<int> lines = new List<int>();
@@ -168,17 +170,22 @@ namespace ICSharpCode.SharpDevelop.Editor
 			get { return textBuffer.TextLength; }
 		}
 		
-		public void Insert(int offset, string text)
+		void IDocument.Insert(int offset, string text)
 		{
 			throw new NotSupportedException();
 		}
 		
-		public void Remove(int offset, int length)
+		void IDocument.Insert(int offset, string text, AnchorMovementType defaultAnchorMovementType)
 		{
 			throw new NotSupportedException();
 		}
 		
-		public void Replace(int offset, int length, string newText)
+		void IDocument.Remove(int offset, int length)
+		{
+			throw new NotSupportedException();
+		}
+		
+		void IDocument.Replace(int offset, int length, string newText)
 		{
 			throw new NotSupportedException();
 		}