Here's what's happening:

Part is modeled. Dimensions are displayed, renamed.

Insert Design table, blank, block changes, uncheck new parameters etc.

Start clicking dimensions to add to cells

Miss next dimension by .000000000000000001", design table disappears.

Edit design table

Can NO LONGER click dimensions and have them added to new cell. Why?

What checkbox do I leave checked so that I can close and open the design table ad infinitum and add new dimensions to the next cell? If I have to keep deleting and re-starting a new design table to try to get all dimensions added in one shot, my laptop's screen is going to have a nice hole through it very soon.