App windows don't fit on eeepc screen?

I’m using Ubuntu 10.4 on my asus eeepc, (for those of you who don’t know). It always occurs that when a window is maximised, it inevitably starts to jump up and down whenever I click anywhere on the window. In this condition, the only way I can get a command to actually work is to aim the cursor over the command button I want, click a couple times, keeping the cursor in that chosen positions and expect the second click to hit the button after the window has shifted up and down again. Quite pathetic. Can’t work like this. What to do?