void OnEndUndo(object sender, Document.UndoOperationEventArgs e)
{
if (e == null)
{
return;
}
e.Operation.Tag = new TextEditorDataState(this, savedCaretPos, savedSelection);
}
void DocumentHandleRedone(object sender, Document.UndoOperationEventArgs e)
{
TextEditorDataState state = e.Operation.Tag as TextEditorDataState;
if (state != null)
{
state.RedoState();
}
}
