Ive started new topic since my last one was pretty long

So thats the question! I dont want a very big control panel so is there a lot/any games using the third button ? I want to use the trackball for games but for windows/interface too. In windows/interface 2 buttons (left/right) is enough. So to save space I would remove the third one from my control panel so instead of having 3 buttons on top of my TB I would place 1 each side of the TB near bottom.
I also assume the third button for games can be mapped at a regular button from P1 or P2 right ?
So is there any real function for that third mouse button ??
Thanks again for all opinions!