C++ – TAB control background in ATL App, XP styles

Have you tried WS_EX_TRANSPARENT?

I think you can set it in the resource editor in Visual Studio, if you're using that.

The usual way of implementing pages in a tab control is required to access MS's solution to this problem :-

Instead of creating individual controls in the tab area, create a modeless child dialog for each page and have the controls on that. Create the page dialogs with the main dialog (not the tab) as their parent and as the user switches between tabs, simply show and hide the relevant page dialog.

In the WM_INITDIALOG handler for each page, call the uxtheme API EnableThemeDialogTexture

With the ETDT_ENABLETAB flag this automatically changes the background color of the dialog and all its child controls to paint appropriately on a tab.

If you have overridden WM_ERASEBKGND or WM_CTLCOLOR* in your pages DialogProc you will need to revert to default handling (return FALSE) as these methods are where the dialog code is going to do its heavy lifting. The style bits should simply be set as though the child page dialog page was going to be created on a normal windows 9X tabbed dialog.