Tab Order and Accessibility panels will not open.

This is very strange.  The page Tab Order and Accessibility dialog panels (upper right corner) no longer open.  When I click on the drop-down links, nothing happens.  I opened some old projects, and they now have the same issue.  So, this appears to be a Captivate 2017 problem, not a corrupted project.  I have re-booted my computer several times.  Note I can still add accessibility text to graphic objects.  Any suggestions would be appreciated.