Button Differences

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 95/98 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 95/98 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 95/98 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).