Comment 7 for bug 310752

Thanks for desire to help, and I attached screen-shots step by step.

As you asked - I turn panel to the top - as it was by default and closed all applications before hand.
Screenshot-1.png - Thunderbird and Pidgin - with wrong icons (Amarok is example of correct window, FireFox works fine too)
Screenshot-2.png - result of click upon Thunderbird maximize icon
Screenshot-3.png - result of click upon Pidgin maximize icon
Screenshot-4.png - result click on Maximize icon for Thunderbird and Pidgin - return them to normal state.