Several people have been reporting problems on MSDN Product Feedback with Visual Studio Beta 2 in which the Editor stops responding to most commands but still allows typing. The good news is that we have identified a fix for the issue, we know how to prevent it and how to get out of the state when it happens. The problem stems from auto-hiding tool windows stealing focus from the editor without actually popping up. To avoid the issue, try not set tool windows to Auto-hide. If you do happen to run into this issue despite the previous advice, then the easiest way to get out of the situation is to activate the tool window by clicking on the tab and then clicking the X in the top right hand corner to close it.
Sean LabereeVisual Studio Editor Team