I modified the check on the windows array to handle the situation that was nil. This was causing breakage for me in when trying to use 3.0.3
Fix for issue #223. Handle situation where windows is nil.
How is the windows array being set to nil? It is initialized to  here.
I'm not sure exactly and would have to look to find a stacktrace. My hunch is that it was through some other code setting the windows instance variable through the attr_accessor.
3-0-stable is no longer maintained, correct? let's close this