Thanks, Sergey

I had, and I've reinstated this, put a .refresh() to the grid after the dynamic sets.

Now here's where I could just say, "Thanks, guys - it's sorted", and sneak off sheepishly, for I've discovered the problem, but I'll be a man and come clean: I was relying on the wrong table. It should have been csrZVARXACT.FIELDVAL and not CENZNFLD.AP_FACTOR.

"csrZVARXACT", as the name suggests, is a transaction table for CENZNFLD. Before I created the xaction table I originally had CENZNFLD as its source, and named it thereafter.

Anyway, the whole form is complicated, it's hot and sweaty here. Thanks for your attention and sorry to waste your time (but it worked like the old show-someone-watching-over-your-shoulder solution to debugging <bg>)

>>So I should do all this in a custom .Refresh() method for the grid?
>
>No but you've to design DynamicColor expresions in such way that they will be properly evaluated at the time of the grid's refresh.