Windows 7: Terminal Server screen won't lock in windows 7

Hi, my office has a terminal server and every time I launch it with dual monitors the terminal server windows do not lock at the maximum size. I can move the entire terminal server window up and down and side to side just by moving the mouse...it is irritating and not allowing me to use the computer efficiently.

I am hoping someone knows how to resolve this problem. If I use 1 monitor, the screen locks and the mouse won't move the entire screen. The other guys in the office with Windows XP do not have this problem either.

Any ideas? Thanks for your help.