void OnBufferTextChanged (object sender, TextChangedEventArgs e)
		{
			if (extension == null)
				((ITextEditorExtension)this).TextChanged (e.StartIndex, e.EndIndex);
			else
				extension.TextChanged (e.StartIndex, e.EndIndex);
		}
		static void BufferTextChanged (object sender, TextChangedEventArgs args)
		{
			LogActiveDocument ();
		}