Hello David
We use the GPen() command to change colours in list boxes. Maybe it is worth a try in the treeview.
We also use ..brushcolour and ..color in tables and they might also be worth a try
Can you turn off the selection colour in the treeview style and then write the select colour in manually as part of the on selection or on entry code and this might allow you to set the colour of the selected node as required ?
Regards
Al