Ubuntu 10.10 and Acer Aspire D150 Visual Issue application windows too big for gnome-desktop

Hello all,

I'm a new user of Ubuntu and overall I'm very pleased with it, but i have one issue which i can't solve and can't find an answer online.

When I open some applications that have quite a big windows (like evolution mail), everytime i click on any space of the application the top bar (the one with the name of the application and the close/minimize/.... botton) appear and disapper and the while windows move up or down at every click, becoming unusable.

Anybody can gelp? Thank you very much!