The parent window of a button (except push buttons) in a version 3.x application receives a WM_CTLCOLORBTN message when the button is about to be drawn. In a version 4.0 application, however, the parent window of a button receives the WM_CTLCOLORSTATIC message, which retrieves a color appropriate for drawing text on the background of the dialog box. Windows 95 sends WM_CTLCOLORSTATIC to retrieve the background and text colors for the text area of check boxes, radio buttons, and group buttons. An application should process WM_CTLCOLORSTATIC in order to correctly set the colors of any dialog box item that contains text and appears directly on the dialog area.
Windows 95 performs default handling of the WM_CTLCOLORBTN message differently depending on an application's version. For a version 3.x application, the default handling for button colors is to use the COLOR_WINDOW value for the background color and the COLOR_WINDOWTEXT value for the foreground color. For a version 4.0 application, Windows 95 uses the COLOR_3DFACE value for the background and the COLOR_BTNTEXT value for the foreground.
In a version 3.x application, a push button's outer top left corner is nonwhite because the button is typically drawn on a white background. If the border was white, the background would appear to bleed into the button. In a version 4.0 application, a push button's outer top left corner is white (COLOR_3DHILIGHT) because the button is typically drawn on a nonwhite background (COLOR_3DFACE).