I am having problems with being unable to hide PM, using the Command-H shortcut or the menu. It works fine initially after PM is started, but at some point stops working. I have not been able to pin down exactly when it becomes unresponsive. PM continues to work perfectly in other respects, but neither Command-H nor the menu item work. Quitting and relaunching fixes the issue. It happens on both my Mac Pro and MacBook Air, both running 10.5.3 and PM 4.5.3.1. Any ideas?