Hi,
I cannot reproduce the issue. After downloading the file you pointed out and running it in VS2012 Debug Mode. I dragged the Alarm Window over the Document1, Clicked the "X" from the Alarm window and the Alarm windows just closed without exceptions.
I cannot reproduce the issue. After downloading the file you pointed out and running it in VS2012 Debug Mode. I dragged the Alarm Window over the Document1, Clicked the "X" from the Alarm window and the Alarm windows just closed without exceptions.