Doing the following steps causes Preview to freeze and require Force Quit. (OS X Lion 10.7.4) 1. Copy some image into your clipboard (e.g. copy picture of screen to the clipboard) 2. Open Preview 3. Press Cmd+N to paste it 4. Make the app fullscreen (top right button) 5. Move mouse to top of screen to make the menu bar appear, go to File->Close Window (don't use Cmd+W shortcut, or the bug won't occur) 6. Don't save changes 7. Preview is frozen Anyone else, or is it just me? If it's not just me... where can we submit a bug report to Apple?