>I have an optiongroup (set of radio buttons) that I am using in the 'Graphical' style so that they look like command buttons. Each individual option object has a backcolor property, yet changing it either during design or run-time appears to have no effect.
Button colors are set via each user's Windows color scheme. To get around it (not recommended, IMHO) you would need to build your own containers that mimic the optiongroup buttons.

>P.S. Can I change anything about the record selector column in a grid with RecordMark turned on? It would be nice to at least change the color of the highlight from black to something else
NAFAIK