pub fn update_colors(
        &mut self,
        focused: Option<WindowHandle<XlibWindowHandle>>,
        windows: &[Window<XlibWindowHandle>],
    ) {
        for window in windows {
            let WindowHandle(XlibWindowHandle(handle)) = window.handle;
            let color: c_ulong = if focused == Some(window.handle) {
                self.colors.active
            } else if window.floating() {
                self.colors.floating
            } else {
                self.colors.normal
            };
            self.set_window_border_color(handle, color);
        }
        self.set_background_color(self.colors.background);
    }
Update all the windows with the new colors.
display-servers/xlib-display-server/src/xwrap.rs