My configuration is Windows 7 x64, with PS running minimized on the tray. There are times when I double-click on the tray icon and nothing seems to happen. I try right-clicking and selecting "Unlock Safe" or "Restore" to no avail; when this happens, I can only make the window appear when I select "Minimize" and then use the Process Explorer utility from Sysinternals (from Microsoft) to bring the window to the front. Other times, the context menu does not even have the "Unlock Safe" option or the "Exit" one; when this happens I cannot even use the Process Explorer to bring up the window, there are simply no options to restore the window, so I have to use the Process Explorer to kill the application.
I can try to provide screenshots if needed.