FAQ.How do I make a metal window if RB does not allow me this?
Feedback.

Answer: The following declare turns any window on Mac OS X 10.2 or newer into a metal one.
Example:

declare sub ChangeWindowAttributes lib "CarbonLib" (win as windowptr, a as integer, b as integer)

ChangeWindowAttributes window1,256,0

Notes: May not look nice depending on the controls used.