It would be nice to be able to set the colours of ShapeButton for more button states, something as :
void ShapeButton::setColours (Colour newNormalColour, Colour newOverColour, Colour newDownColour, Colour newDisabledColour , Colour newNormalOnColour, Colour newOverOnColour, Colour newDownOnColour, Colour newDisabledOnColour)
cause without the disabled and ON colours, it's often that ShapeButton can't be used.
Or perhaps better, its paintButton() should call a lookandfeel method which would use eight ShapeButton::ColoursIDs,
and the already existing setColours() fonction should be marked as depreciated and modified to just set 3 colourIDs.