PureBasic Forums - English

SetClassLong_(GadgetID(hContainer), #GCL_HBRBACKGROUND, hBrush)

Allthough it looks like it works, is it officially supported?
(In rare cases the background isn't updated when needed)

No API commands are officially supported. If there are rare cases where the background isn't being updated, there's likely something to find in your code. Note that if you're using a SolidBrush, you can accomplish the same goal natively with SetGadgetColor. For PatternBrush, a good native alternative is a disabled image gadget.