Arh! The problem (from msdn):
"Normally, if you wanted the dialog bar band to appear transparent, you would set the WM_EX_TRANSPARENT extended style for the dialog bar object. However, because WM_EX_TRANSPARENT has some issues with properly painting the background of a dialog bar, you will need to do a little extra work to achieve the desired effect"
What this means is when you attach a child window (dialog bar) to a rebar control, the background is not drawn correctly if you use anything in the background (a color or bitmap) - under XP (using XP styles), the problem becomes more apparent since the rebar is drawn with the current style.
A solution is to this problem is presented in the following links:
However, both of these solutions require you to handle the WM_ERASEBKGND message and pass it to the parent control - is this kind of thing you can do with Hook?
----- Original Message -----
From: Jez White
To: Win32-GUI ; Steve Pick
Sent: Monday, February 23, 2004 11:16 AM
Subject: [perl-win32-gui-users] Hook and WM_ERASEBKGND

I'm still playing with rebars, and have come across an interesting problem:) To quote from msdn: