When you drag a button onto a Window, the border seems to paint the colour of the background that it is first placed onto so that the anti-aliasing smoothly transitions to the background colour (due to the button effect being a raster effect rather than vector I presume).
I’ve noticed that this colour isn’t re-applied properly after turning the Border Painted? property off and back on again, see screenshot - Cancel button border is “white”, compared with the Accept button:
Is there any way to get this to re-apply, aside from dragging on a new button? This would also help when moving the button onto another background colour as well.
The same equally applies to the other raster effects (field border as one other example)