Mouse does not function correctly in middle portion of screen

The middle area of the screen no longer responds to the presence of the mouse pointer (mouse-over highlights) or to mouse clicks when then mouse pointer is present. Regular gameplay seems unaffected until a GUI is opened. Reducing the size of the window and moving it around in the screen serves as a workaround. The dead area is roughly the middle third of the screen horizontally, and approximately the middlemost 50% vertically.

EDIT: Nevermind, it seems to have resolved itself.