I'm currently running VS2013 Update 2 RC. This just started this morning, and I can't seem to find anything on the system that changed in the last few days.
Whenever I hit a breakpoint, all of the visible windows are frozen in place. I can't tell if they are locked up, but they are visually frozen. If I alt+tab, it also becomes frozen on the screen. However, visual studio remains responsive and working. If I stop the debugger, everything goes back to normal. I can't bring up the task bar (it's normally collapsed), and I can't use any other applications besides VS. If I set the taskbar to not be hidden and recreate the problem, when I mouse over it the cursor turns to the wait cursor and the taskbar appears to be locked up. So far the problem happens when I'm debugging C# and TypeScript. I haven't tried it on anything else.
Like I said, this just started happening today. My machine has been very stable and hasn't had any updates or software installed in a couple of weeks.
Thanks.