chore: reduce component overhead (#3)

Reviewed-on: #3

crates/core/tests/dropdown_menu.rs

@@ -322,3 +322,136 @@ fn disabled_trigger_ignores_clicks() {
     assert!(changes.borrow().is_empty());
     assert!(visual.debug_bounds("menu-panel").is_none());
 }
+
+struct PairHarness {
+    open_a: bool,
+    open_b: bool,
+    changes_a: Changes,
+    changes_b: Changes,
+    activated_a: Activated,
+    activated_b: Activated,
+}
+
+impl Render for PairHarness {
+    fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
+        let (changes_a, changes_b) = (self.changes_a.clone(), self.changes_b.clone());
+        let (activated_a, activated_b) = (self.activated_a.clone(), self.activated_b.clone());
+
+        let menu_a = DropdownMenu::new("pair-a")
+            .label("Alpha")
+            .variant(ButtonVariant::Secondary)
+            .open(self.open_a)
+            .on_open_change({
+                let view = cx.entity();
+                let changes = changes_a.clone();
+                move |next, _, cx| {
+                    changes.borrow_mut().push(next);
+                    view.update(cx, |harness, cx| {
+                        harness.open_a = next;
+                        cx.notify();
+                    });
+                }
+            })
+            .items(move |_, _| {
+                vec![
+                    MenuItem::new("png").handler({
+                        let activated = activated_a.clone();
+                        move |_, _| activated.borrow_mut().push("png")
+                    }),
+                    MenuItem::new("pdf").handler({
+                        let activated = activated_a.clone();
+                        move |_, _| activated.borrow_mut().push("pdf")
+                    }),
+                ]
+            });
+
+        let menu_b = DropdownMenu::new("pair-b")
+            .label("Beta")
+            .variant(ButtonVariant::Secondary)
+            .open(self.open_b)
+            .on_open_change({
+                let view = cx.entity();
+                let changes = changes_b.clone();
+                move |next, _, cx| {
+                    changes.borrow_mut().push(next);
+                    view.update(cx, |harness, cx| {
+                        harness.open_b = next;
+                        cx.notify();
+                    });
+                }
+            })
+            .items(move |_, _| {
+                vec![
+                    MenuItem::new("zip").handler({
+                        let activated = activated_b.clone();
+                        move |_, _| activated.borrow_mut().push("zip")
+                    }),
+                    MenuItem::new("7z").handler({
+                        let activated = activated_b.clone();
+                        move |_, _| activated.borrow_mut().push("7z")
+                    }),
+                ]
+            });
+
+        div().size_full().flex().gap_2().child(menu_a).child(menu_b)
+    }
+}
+
+fn pair_window() -> (
+    VisualTestContext,
+    AnyWindowHandle,
+    Changes,
+    Changes,
+    Activated,
+    Activated,
+) {
+    let mut cx = TestAppContext::single();
+    cx.update(Theme::init);
+    let changes_a = Rc::new(RefCell::new(Vec::new()));
+    let changes_b = Rc::new(RefCell::new(Vec::new()));
+    let activated_a = Rc::new(RefCell::new(Vec::new()));
+    let activated_b = Rc::new(RefCell::new(Vec::new()));
+    let (changes_a_for_window, changes_b_for_window) = (changes_a.clone(), changes_b.clone());
+    let (activated_a_for_window, activated_b_for_window) =
+        (activated_a.clone(), activated_b.clone());
+    let window = cx.add_window(move |_, _| PairHarness {
+        open_a: false,
+        open_b: false,
+        changes_a: changes_a_for_window,
+        changes_b: changes_b_for_window,
+        activated_a: activated_a_for_window,
+        activated_b: activated_b_for_window,
+    });
+    let window = window.into();
+    cx.update_window(window, |_, window, cx| {
+        window.draw(cx).clear(cx);
+    })
+    .unwrap();
+    (
+        VisualTestContext::from_window(window, &cx),
+        window,
+        changes_a,
+        changes_b,
+        activated_a,
+        activated_b,
+    )
+}
+
+/// With a closed sibling dropdown on screen, a pointer-opened menu must still
+/// arm rows with the keyboard: the menu's open/selection state is per
+/// instance, not shared keyed state.
+#[test]
+fn sibling_dropdowns_keep_independent_menu_state() {
+    let (mut visual, window, changes_a, changes_b, activated_a, activated_b) = pair_window();
+
+    // Menu A sits at the window's top-left; menu B stays closed beside it.
+    click(&mut visual, point(px(30.), px(14.)));
+    assert_eq!(*changes_a.borrow(), vec![true]);
+    draw(&mut visual, window);
+
+    visual.simulate_keystrokes("down enter");
+    assert_eq!(*activated_a.borrow(), vec!["png"]);
+    assert_eq!(*changes_a.borrow(), vec![true, false]);
+    assert!(changes_b.borrow().is_empty(), "B must stay closed");
+    assert!(activated_b.borrow().is_empty());
+}