private void setWindowBackground( int r, int g, int b ) {
			// delete old background brush
			if( background != null )
				GDI32.INSTANCE.DeleteObject( background );

			// create new background brush
			background = GDI32Ex.INSTANCE.CreateSolidBrush( RGB( r, g, b ) );
		}
Because there may be sent many WM_DWMCOLORIZATIONCOLORCHANGED messages,
slightly delay event firing and fire it only once (on the AWT thread).
flatlaf-natives/flatlaf-natives-jna/src/main/java/com/formdev/flatlaf/natives/jna/windows/FlatWindowsNativeWindowBorder.java