All windows lock while File open dialog is up. I first discovered this when I thought my browser, and all instances of it were frozen..but then as I started minimizing the windows and getting ready to kill them, I found that I had an Attach File dialog open in the background. I was then able to duplicate the same problem with a URL open from the web browser. It locks up the browser window, which is understandable, but locking up ALL instances of the browser that are running. Very confusing behavior.

*** This bug has been marked as a duplicate of 65521 ***