Steps to reproduce problem on OS X:
- Open Xamarin Studio 6.1 (build 817)
- Create new Xamarin Forms app solution
- File -> New Project ---- don't interact with the New Project modal window that appears
- Minimize Xamarin Studio
- Switch back to Xamarin Studio (re-open window)
- Attempt to create a new project, add a new file to a project, or close Xamarin Studio using the red close-window button -- these do not work at this point. Xamarin Studio must be forced to quit/restart to function correctly again.