Update: In BeOS 5, Alt+PrintScrn no longer drops you into the debugger, so this tip isn’t much of a warning anymore. If you do want to drop into the debugger, hit Alt+PrntScrn+D.
If you’re coming from the Windows world, you may be accustomed to using the Alt+PrintScreen key to limit your screenshots to the active object. Don’t try this in BeOS! This key combination drops you into the kernel debugger (the PrintScreen key doubles as the SysReq key). However, if you don’t have serial debugging enabled and aren’t watching the output on another screen, it will appear that your system has just locked up. For all intents and purposes, it has.
So: A) this is a feature, not a bug. Don’t bother reporting it. B) Don’t try it unless you’ve saved all your work and you’re ready to lock up your system.