As a workaround I added a second shape with the formatting I wanted.
And then added custom code to swap the visibility of the two controls.
Ugly but… works for me, for now.
I am still looking at this problem too, please share if you figure it out.
I thought that turning off AppStyling on the control would be all I needed to get code to work but… I only see the control changes flash and then “something” immediately resets the colors.TBD what…
and here is a previous topic with some examples of fiddling with shapes/colors