Prosteel Detail Center Express Issue

A problem popped up rather suddenly and I can't figure out if the problem is an option I may have accidentally selected or if it will require a reinstall of the Prosteel Software.  

The Problem:  While running Prosteel DetailCenter Express, on the 'Assign Detail Style to Single Parts' page (or Groups, assemblies, or views as well) the option to shift detail styles back and forth from 'Assigned' to 'Not Assigned' is disabled.   And this problem is not restricted to only one file... it is happening in every project I try preparing drawings for.

Has anyone encountered this problem before?  And solutions?

Bernie