I dont even know if i can get into that part, it requires taking out just about everything! I'll have to try it when i get some free time and see if there is something to tighten. It would help if someone knew i can push it back to shape but it just goes back to sticking out if i let go
Dude, inside the case there are a number of Torx screws holding the 'handle' to the body of the case. I can only imagine those screws have since come loose... Did you try tightening them using a mini Torx wrench? Unfortunately, you might have to dissemble parts of the machine to get at those screws.
Here's a link to someone's awesome G5 case mod,
it'll probably give you some idea as to how the MacPro case is assembled: