Storyboard Pro minimizes and won't come back

Has anyone else come across Storyboard Pro suddenly minimizing and essentially disappearing? All I see is the File menu at the top. I can temporarily ‘fix’ it by making the program ‘full screen’ but if I turn full screen off it minimizes again. What’s worse is that when it’s minimizing it’s not on the dock either. Any idea how to fix this problem? It happens in SBP4 as well as SBP 5 (and 5.1)

Yes. This happens to me if I go to full screen and switch layouts or even open a new file. One workaround is to not use OS X full screen mode, or to switch workspaces and back again so that the window restores itself.

Thanks!