An interesting BUG that's been in the last several versions (at least since 3.0) of Amiga OS is switching screens via the depth gadget while a window is trying to open on one of the screens. If you time it just so, Intuition stops responding to the mouse or the keyboard (except for CTRL-AMIGA-AMIGA of course). I've tried to get the attention of those working on AmigaOS as to this bug several times, but never heard anything back. Not even an "I can't reproduce that" type of message.