Can't drive model with drawing dimensions - read only

I have been unable to drive model dimensions from the assembly/drawings. "Read only" is checked and greyed out so that I cannot uncheck.  The model views are updated as I modify the Sldprt file models, but the dimensions aren't updating with them, and are shown in grey all the time.  I have been through all document properties and options and checked the ext. ref's  but still cannot figure it out.  Please help!

SolidworksDrawings And Detailing