Ubuntu 11.04, and therefore Mint 11, uses a VERY buggy version of Compiz that (in my opinion) should have never made it to release. Below is the way I've found to get the older, stable version of Compiz back until they've worked out the nasty little bugs:
1. Open Synaptic (Package Manager) and type Compiz into the Quick Search bar.
2. Uninstall all Compiz-related packages by clicking on the green box to the left of each, selecting Uninstall, and when they're all marked, click Apply.
3. In Synaptic (Package Manager), go to Settings -> Repositories.
4. Click on the Other Software tab.
5. Click Add.
6. In the APT line box, type or cut/paste the following: ppa:guido-iodice/compiz-0.8.6-natty
7. After exiting the sources manager, reload your sources (click the Reload button on Synaptic).
8. Install the same Compiz-related packages that you just removed (look at File -> History and click on today's date if you've forgotten) by selecting the grey box to the left of each package, selecting Install, and when they're all marked, click Apply. There is one exception to this. Fusion-icon won't install because of dependency issues.
9. If you need a replacement for Fusion-icon, go to
http://sourceforge.net/projects/displex ... lex-0.7.1/. It has many of the same functions as Fusion-icon. Click on displex-0.7.1-all.deb, and save it to your desktop. From the desktop, right-click on the file you just downloaded, and select Open with Gdebi Package Installer. Click Install.
Sorry if I've gone a little overboard with the details. I want to make sure the newest of newbies can figure this out. Hope this helps someone. I was having all sorts of Compiz-related problems before doing this. Now I've got full functionality back.