Hi. When I click the mouse, or generate any event whatsoever other than motion, the Nexuiz client seemingly assumes I wish to move my mouse to the right bottom corner.

I looked into this and I believe I may have found the problem.

Using "xev," (i'm running this on Ubuntu) I found that unlike most mice mine generates a mouse movement event upon clicking or generating any other event. There should be no problem, however, as the event's coordinates are EXACTLY the same as the click's.

I'm guessing it is a bug in Nexuiz, due to the fact that even upon inverting mouse input, the mouse jumps to the same corner.

Perhaps there's something in there that doesn't like a mouse movement event to the position it's already at. Maybe you guys could have a look? I'll see if I can paw through the code and find the input routines, but I figured I'd post here first.

This sounds more like a problem with the mouse. I've had the same problem when I was using a low quality mouse on a semi-reflective surface. The difference is that I was working in windows, I wasn't in-game.
Try with another mouse, just to be sure.