I have installed the add-ons MinimizedToTray revived 1.0.1 to Thunderbird, as suggested here. Even though the main functionality of hiding TBird to the tray works well, after a while (minutes) on maximizing it, the menus of TBird are gone form the unity panel. So I have no File/Edit/View ... etc menus. That kills the joy of minimizing it to the tray a bit.
Is there a problem between this add-on and Unity on 12.04?