Lion => Mountain Lion; Inspector is hung, Files won't open (Help!)

I upgraded to OS X Mountain Lion from Lion over the weekend.  Everything seemed to work fine, although was prompted to install new JRE first time I ran RubyMine (4.5.4) after upgrade.

Now, I am seeing that the code inspector appears to be hung -- the little icon in the upper left of the editor window shows the "eye" image, and reports "Performing Code Analysis" indefinitely.  I have stopped and restarted RubyMine.  The * in the bottom status bar reports no active background processes.  If I introduce an error, nothing changes.  I tried changing the settings of inspections.  I tried going into Power Save mode (disables inspections) and then back.

Any ideas?

Tom