Fixed SD2-1087: Setting IEditable.Text does not update undo stack

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/branches/2.1@2262 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/DefaultDocument.cs

@@ -223,6 +223,7 @@ namespace ICSharpCode.TextEditor.Document
 				OnDocumentAboutToBeChanged(new DocumentEventArgs(this, 0, 0, value));
 				textBufferStrategy.SetContent(value);
 				lineTrackingStrategy.SetContent(value);
+				undoStack.ClearAll();
 				
 				OnDocumentChanged(new DocumentEventArgs(this, 0, 0, value));
 				OnTextContentChanged(EventArgs.Empty);

src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/IDocument.cs

@@ -193,7 +193,10 @@ namespace ICSharpCode.TextEditor.Document
 
 #region ITextBufferStrategy interface
 		/// <value>
-		/// Get the whole text as string
+		/// Get the whole text as string.
+		/// When setting the text using the TextContent property, the undo stack is cleared.
+		/// Set TextContent only for actions such as loading a file; if you want to change the current document
+		/// use the Replace method instead.
 		/// </value>
 		string TextContent {
 			get;

src/Main/Base/Project/Src/TextEditor/Gui/Editor/TextEditorDisplayBinding.cs

@@ -209,7 +209,7 @@ namespace ICSharpCode.SharpDevelop.DefaultEditor.Gui.Editor
 		
 		void SetText(string value)
 		{
-			textAreaControl.Document.TextContent = value;
+			textAreaControl.Document.Replace(0, textAreaControl.Document.TextLength, value);
 		}
 		
 		public string Text {