So, I've been running Blender for a while now, and in the updates between now and about six months ago, I've had an annoyingly persistent issue pop up.
After some time working in Blender, the UI will spontaneously decide that it doesn't like me anymore and blank out any portion of the interface that I'm not directly interacting with. There doesn't seem to be a specific amount of time before it triggers, and it isn't triggered by a particular action on my part. What it does do is make working on anything at all a process of 'work until it freaks out, save, shut down, start up and get back to work'.
Is anyone else having this issue, and more importantly, has anyone figured out what's going on and how to stop it?
Intel video chipset by chance?
Try changing the Window Draw Method in the User Preferences : System section.
Also, make sure your video drivers are up to date.
-- Input devices for a 3D world.
Spacemice / Blender Compatibility