Continuous Grab (Mouse Wrapping Screen during Transforms) Stopped Working... HELP!

I love the “Continuous Grab” feature of Blender. For those who don’t know, it’s when you’re translating/scaling/rotating/etc and when you’re mouse goes off the edge of the screen it wraps around to the other side, but doesn’t interrupt the transform in progress.
Well for some reason today I noticed my mouse wasn’t wrapping. I’m using Blender 2.74 on Windows 7 x64. In User Preferences -> Input, I’ve triple checked that “Continuous Grab” is checked. But for some reason it never wraps my mouse. Any ideas?