User-Agent:       
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040207 Firefox/0.8

If a Save As dialog for a nonexistent window exists, when the dialog is closed Firefox will crash.  It's possible to cause this to happen using the "Open With/Save As" dialog.

Reproducible: Always
Steps to Reproduce:
1. Visit http://www.mozilla.org/products/firefox/
2. Click on "Download Now!"  An "Open With/Save" dialog will appear.
4. Press OK.
5. Switch back to the "Open With/Save" dialog, and press OK again.  There are now two Save As dialogs.  This is bug 58777.
6. Close the second dialog with "Cancel"
7. Close the browser window that started all of this.
8. Close the first dialog with "Cancel".

Actual Results:  
Crash!

Expected Results:  
Not crashed.