Steps to reproduce, using compiz 0.5 on a gnome desktop:
1. Open a gnome session and start compiz.
2. Right-click on top panel and select "Add to Panel ..."
3. With the "Add to Panel" dialog still open, launch Terminal from the main gnome menu.
4. Drag the Terminal window downwards using the mouse, until it reaches the bottom panel.
Expected result: The Terminal window is drawn underneath the bottom panel.
Actual result: The Terminal window is drawn over the bottom panel.
Mass closure: This bug has been untouched for more than six years, and is not
obviously still valid. Please reopen this bug or file a new report if you continue to experience issues with current releases.