add overlay for testing

src/widgets/menu/menu_bar_overlay.rs

@@ -462,6 +462,27 @@ where
         );
     }
 
+    fn overlay<'c>(
+        &'c mut self,
+        layout: Layout<'_>,
+        renderer: &Renderer,
+    ) -> Option<overlay::Element<'c, Message, Theme, Renderer>> {
+        let bar = self.tree.state.downcast_ref::<MenuBarState>();
+        let active = bar.active_root?;
+        let mut lc = layout.children();
+        let _bar_bounds = lc.next()?.bounds();
+        let _roots_layout = lc.next()?;
+        let menu_layouts_layout = lc.next()?; // Node{0, [menu_node...]}
+        let mut menu_layouts = menu_layouts_layout.children(); // [menu_node...]
+        let active_root = &mut self.roots[active];
+        let active_tree = &mut self.tree.children[active];
+        let menu = active_root.menu.as_mut()?;
+        let menu_tree = &mut active_tree.children[1];
+        let menu_layout = menu_layouts.next()?;
+
+        menu.overlay(menu_tree, menu_layout, renderer, Vector::ZERO)
+    }
+
     fn draw(
         &self,
         renderer: &mut Renderer,