I have to click the 'red X' and click OK on the dialog that pops up asking me to end the program that is not responding.
Other than that I can't report much of anything other than when I last checked the window it was fine and I had just uploaded one or more files without any problem.
This just started, I am pretty sure, after the latest update 4.3.3. Build 1340 was installed via an update from the previous version.
Is there something I can enable or look for to give some kind of indication what happened? I realize this is nothing to go on by just saying it was unresponsive.