!WIN_FLAT
Windows only. When set, globally eliminates the default 3D perspective for Windows widgets such as buttons, text fields, and so forth. This variable must be set at run time, before the target widget is created, to have an effect. It may be changed while the application is running. Scrollbars are owned by the Window’s window manager and are unaffected by this setting.
This system variable, used alone or together with !WIN_NO_BORDER, globally transforms the appearance of existing PV-WAVE Windows widget applications into the new, flat style of Windows Metro applications.