I just made a namespace refactoring on a project and it looks like Resharper hangs while executing it. It took me some time to realize that the progress dialog hides another modal dialog (the performance warning for opening many files).
I canceled the refactoring and repeated it. I noticed that the second dialog was immediatly hidden by the progress dialog. The first time i didn't see this because i leaved my desk while the refactoring was running.