I have a 13" Core2 MacBook, the pre-Santa Rosa model. Recently, the keyboard shortcuts for taking screenshots have randomly stopped working, though they are still checked in System Preferences. If I double-click on the shortcut and re-assign the same (or different) keys, the shortcuts work again. This occurs with both 10.5.2 and 10.5.3. Has this happened to anyone else? If so, what did you do about it?