ContainerControls
Today I learnt that in RB 2009r2.1 (Still my favorite RB version) the ContainerControl.EmbedWithin places the controls on front on Windows and on the back on Mac OS X.
That is the reason I now have a canvas on the Mac side. So I can embed a second layer not on the window, but on the canvas to have it on front. On Windows I can simply embed to the window.