Fix tooltips still being drawn over

Simply use the list of event dispatchers like the old code did.

src/gui/core/event/handler.cpp

@@ -146,6 +146,11 @@ class sdl_event_handler : public events::sdl_handler
 	 */
 	void disconnect(dispatcher* dispatcher);
 
+	/**
+	 * Returns all dispatchers in the Z order.
+	 */
+	std::vector<dispatcher*>& get_dispatchers() { return dispatchers_; }
+
 	/** The dispatcher that captured the mouse focus. */
 	dispatcher* mouse_focus;
 
@@ -807,6 +812,12 @@ void disconnect_dispatcher(dispatcher* dispatcher)
 	handler_->disconnect(dispatcher);
 }
 
+std::vector<dispatcher*>& get_all_dispatchers()
+{
+	assert(handler_);
+	return handler_->get_dispatchers();
+}
+
 void init_mouse_location()
 {
 	point mouse = get_mouse_position();

src/gui/core/event/handler.hpp

@@ -247,6 +247,11 @@ void connect_dispatcher(dispatcher* dispatcher);
  */
 void disconnect_dispatcher(dispatcher* dispatcher);
 
+/**
+ * Gets all event dispatchers in the Z order.
+ */
+std::vector<dispatcher*>& get_all_dispatchers();
+
 /**
  * Initializes the location of the mouse.
  *

src/gui/widgets/window.cpp

@@ -1225,15 +1225,12 @@ void window_swap_grid(grid* g,
 
 void window::redraw_windows_on_top() const
 {
-	auto me = std::find(open_window_stack.begin(), open_window_stack.end(), this);
-	if(me == open_window_stack.end()) {
-		// Known to happen for tooltips.
-		return;
-	}
+	std::vector<dispatcher*>& dispatchers = event::get_all_dispatchers();
+	auto me = std::find(dispatchers.begin(), dispatchers.end(), this);
 
-	for(auto it = std::next(me); it != open_window_stack.end(); ++it) {
+	for(auto it = std::next(me); it != dispatchers.end(); ++it) {
 		// Note that setting an entire window dirty like this is expensive.
-		(*it)->set_is_dirty(true);
+		dynamic_cast<widget&>(**it).set_is_dirty(true);
 	}
 }