Open ccsm  first

In the Opacity Windows text field, you have to input a pipe-separated list of window types to which you want to apply the transparency. I use the following string:

Tooltip | Menu | PopupMenu | DropdownMenu

Then I set the Opacity Window Values field to 90 to indicate that windows of the previously specified types should be 90 percent opaque and 10 percent transparent.

You can also use more elaborate window matching strings that use window class, role, and title. For instance, I like to make all of my Pidgin conversation windows slightly transparent, but not the buddy list. In order to do that, I assign 95 percent opacity to all windows that use the Pidgin class and use the buddy list window title to exclude it from the match list. This is the string I use in the Opacity Windows text box for my Pidgin transparency:

class=Pidgin & !title=Buddy List