I am experiencing the exact same issue as this fellow, and cant seem to find any real solutions to the issue. The only solution I've been able to find so far that works it not maximizing VS. Keeping VS in windowed mode fixes the problem completely, but as soon as it returns to maximized state UI elements no longer redraw unless the stale area is put under new active focus. This makes it impossible to develop and I'm forced to return to windowed mode. I've tried disabling hardware acceleration with no luck. Any Ideas?
There are a handful of feedback reports at connect.microsoft.com that describe a similar problem. But none that ever evolved to a solution, most typically the programmer that filed the report stopped responding when asked to provide additional diagnostics.
Clearly this is an environmental problem, something is wrong with your machine. VS2012 uses WPF for rendering, it puts non-trivial demands on the machine. You do need a solid video driver and a functional DirectX stack to make it work without problems. This tends to be an issue in general, video drivers are by far the most problematic kind of driver. Problems are roughly correlated with the age of the machine and how old the operating system is.
So a good starting point is to look for a video driver update first, visit the web site of the company that made your adapter to look for the latest. Reinstall DirectX on the machine next. If you were considering a clean update of your machine before, like updating the Windows version, now would be a good time to start with a clean slate.