ALT key freezes drawing window

[3drodriguez]

Whenever I press the ALT key, which is a shortcut to the eraser and scale mode, the program visually freezes the drawing window. I have to repress my ALT key to regain vision of any changes in the drawing window. The program allows me to continue to drawing when frozen, but doesn't display any changes until I press my ALT key to unfreeze the drawing window. The rest of the program remains responsive and I'm able to change brushes and click menus, just not a visually accurate drawing window.