Change Background color of a Specific window?

Is there a way to change the background color of an app (such as MS Calculator), without changing the background color system-wide?

I want to change the color of a specified window, just as if I were to change the system-wide color for "3D Objects", but I want to override the default operating system colors for just a specific window handle.

I don't known if I have undestand...

myForm.backcolor=vbgreen
myform.backcolor=RGB(0,255,0)
myForm.backcolor=&h00ff00

but it's a right codes for your problem?

<center>
<HR width=80%>
<img src='http://web.tiscali.it/bertaplanet/im...ertaplanet.gif'>
</center>

Im not sure if it of any use, but if you can get the HdC of and window you can use the Declare Function PaintDesktop Lib "user32" Alias "PaintDesktop" (ByVal hdc As Long) As Long call to paint the desktop wallpaper/colour onto the window. There may be a call specific to your needs, get the API viewer from allapi.com.