Ensure that GUI1 widgets are drawn on a DRAW_ALL_EVENT

The DRAW_ALL_EVENT is only used in certain circumstances, when a full
redraw of all widgets/components is desired. The previous behaviour
relied on a DRAW-event following the DRAW_ALL_EVENT, which is not
something that can be relied upon. By calling draw() explicitly it
removes the reliance on the DRAW-event.

src/widgets/widget.cpp

@@ -345,6 +345,7 @@ void widget::process_tooltip_string(int mousex, int mousey)
 void widget::handle_event(SDL_Event const &event) {
 	if (event.type == DRAW_ALL_EVENT) {
 		set_dirty();
+		draw();
 	}
 }