Merge PR #7957: Fix dropdown menus opening behind modal dialogs on macOS trackpad tap (#7113)

crates/ui-egui/src/crop_presets.rs

@@ -142,7 +142,9 @@ pub fn dropdown(app: &mut PhotocraftApp, ui: &mut egui::Ui) {
     let current_user = users.iter().rev().find(|(_, f)| matches(o, f)).map(|(n, _)| n.clone());
     let can_new = savable(o).is_some();
     let mut chosen: Option<Choice> = None;
+    let parent_layer = ui.layer_id();
     egui::ComboBox::from_id_salt("crop-ratio").selected_text(label).width(140.0).height(420.0).icon(crate::widgets::chevron_icon).show_ui(ui, |ui| {
+        crate::press_menu::above_parent_ui(parent_layer, ui);
         let (before, after): (Vec<_>, Vec<_>) = builtin.iter().partition(|(k, _)| k != crop_size::FRONT);
         for (k, l) in &before {
             if ui.selectable_label(current_user.is_none() && *k == o.crop_ratio, tl!(l)).clicked() {

crates/ui-egui/src/dropdown_press_tests.rs

@@ -74,3 +74,56 @@ fn a_click_still_opens_the_list_for_a_second_click() {
     h.run_steps(3);
     assert_eq!(blend(&h), BlendMode::Screen, "a second click picks");
 }
+
+/// #7113: on macOS a trackpad tap-to-click delivers `Pressed` and `Released` in the same frame,
+/// which raises both the modal dialog (`pointer_pressed_on_area`) and the reopened ComboBox popup
+/// (`!visible_last_frame`) in the same pass. When the popup's static LayerId already sits before
+/// the dialog's in `Areas::order` (from an earlier open or `ui.ron`), egui's stable sort left the
+/// dropdown menu behind the dialog window.
+#[test]
+fn single_frame_trackpad_tap_keeps_dialog_dropdown_above_modal_and_selects_option() {
+    let mut h = app_with_a_layer();
+    let tap = |h: &mut Harness<'_, PhotocraftApp>, at: egui::Pos2| {
+        h.input_mut().events.push(egui::Event::PointerMoved(at));
+        for pressed in [true, false] {
+            h.input_mut().events.push(egui::Event::PointerButton { pos: at, button: egui::PointerButton::Primary, pressed, modifiers: egui::Modifiers::NONE });
+        }
+        h.run_steps(3);
+    };
+
+    // First dialog: open the Palette dropdown once so its static popup LayerId enters `Areas::order`,
+    // then close the dialog.
+    let d1 = crate::filter_dialog::open(h.state_mut(), "image.mode.indexedColor").unwrap();
+    h.run_steps(3);
+    let palette_box = blend_box(&h, "Selective").center();
+    tap(&mut h, palette_box);
+    assert!(egui::Popup::is_any_open(&h.ctx));
+    crate::dialogs::cancel(h.state_mut(), d1).unwrap();
+    h.run_steps(2);
+
+    // Second dialog gets a newer `("dialog", d2)` LayerId placed after the popup's static LayerId
+    // in `Areas::order` (the same ordering `ui.ron` restores across launches).
+    let d2 = crate::filter_dialog::open(h.state_mut(), "image.mode.indexedColor").unwrap();
+    h.run_steps(3);
+    let palette_box = blend_box(&h, "Selective").center();
+    let dialog_layer = h.ctx.layer_id_at(palette_box).expect("dialog layer at ComboBox");
+
+    // 1-frame trackpad tap on the Palette dropdown: the list must open IN FRONT OF the dialog.
+    tap(&mut h, palette_box);
+    assert!(egui::Popup::is_any_open(&h.ctx), "tap opens the dropdown");
+    let perceptual_pos = h.get_by_label("Perceptual").rect().center();
+    let top_at_item = h.ctx.layer_id_at(perceptual_pos);
+    assert!(
+        top_at_item.is_some() && top_at_item != Some(dialog_layer),
+        "#7113: dropdown popup layer ({top_at_item:?}) must be above the modal dialog ({dialog_layer:?})"
+    );
+
+    // Second 1-frame trackpad tap on "Perceptual" selects it and closes the list.
+    tap(&mut h, perceptual_pos);
+    assert!(!egui::Popup::is_any_open(&h.ctx), "tap on option closes the dropdown");
+    assert_eq!(
+        h.state().ui.dialogs.iter().find(|d| d.id == d2).and_then(|d| d.fields.get("palette")).and_then(|v| v.as_str()),
+        Some("perceptual"),
+        "tap on Perceptual selected it"
+    );
+}

crates/ui-egui/src/layer_style/contour.rs

@@ -105,7 +105,9 @@ pub(super) fn row(ui: &mut egui::Ui, f: &mut Map<String, Value>, effect: &str, k
             open = !open;
         }
         let mut chosen: Option<&str> = None;
+        let parent_layer = arrow.layer_id;
         egui::Popup::from_response(&arrow).open_bool(&mut open).close_behavior(egui::PopupCloseBehavior::CloseOnClickOutside).show(|ui| {
+            crate::press_menu::above_parent_ui(parent_layer, ui);
             ui.spacing_mut().item_spacing = vec2(4.0, 4.0);
             egui::Grid::new(("contour-presets", effect, key)).spacing(vec2(4.0, 4.0)).show(ui, |ui| {
                 for (i, (name, _)) in CONTOURS.iter().enumerate() {

crates/ui-egui/src/press_menu.rs

@@ -79,6 +79,22 @@ impl PressMenu {
     }
 }
 
+/// Keep an open popup or dropdown layer above `parent` when `parent` is also in
+/// [`egui::Order::Foreground`] (a modal dialog or popover, #7113): a 1-frame trackpad tap raises
+/// both the parent modal (`pointer_pressed_on_area`) and the reopened popup (`!visible_last_frame`)
+/// in the same pass, and egui's stable `wants_to_be_on_top` sort then leaves a previously used
+/// popup behind the dialog.
+pub fn above_parent(ctx: &egui::Context, parent: egui::LayerId, child: egui::LayerId) {
+    if parent.order == child.order && parent != child {
+        ctx.set_sublayer(parent, child);
+    }
+}
+
+/// [`above_parent`] for an open popup's `Ui`.
+pub fn above_parent_ui(parent: egui::LayerId, popup_ui: &egui::Ui) {
+    above_parent(popup_ui.ctx(), parent, popup_ui.layer_id());
+}
+
 /// Shows `button`'s menu (an `egui::Popup::menu`) with press-drag-release; `content` chooses its
 /// items with [`PressMenu::item`].
 pub fn show<R>(button: &Response, content: impl FnOnce(&mut Ui, &PressMenu) -> R) -> Option<R> {
@@ -89,6 +105,9 @@ pub fn show<R>(button: &Response, content: impl FnOnce(&mut Ui, &PressMenu) -> R
     // close it again.
     let close = if button.clicked() && menu.owns_gesture(&ctx) { PopupCloseBehavior::IgnoreClicks } else { PopupCloseBehavior::CloseOnClick };
     let shown = Popup::menu(button).open_memory(open).close_behavior(close).show(|ui| content(ui, &menu)).map(|r| r.inner);
+    if shown.is_some() || Popup::is_id_open(&ctx, menu.popup) {
+        above_parent(&ctx, button.layer_id, egui::LayerId::new(egui::Order::Foreground, menu.popup));
+    }
     // This menu's gesture ends with the button (its release was handled by the items above).
     if menu.owns_gesture(&ctx) && ctx.input(|i| i.pointer.primary_released() || !i.pointer.primary_down()) {
         ctx.data_mut(|d| d.remove::<egui::Id>(gesture_id()));
@@ -150,6 +169,9 @@ impl PressCombo {
         } else if self.owns_gesture(ctx) && ctx.input(|i| i.pointer.primary_released() || !i.pointer.primary_down()) {
             ctx.data_mut(|d| d.remove::<egui::Id>(gesture_id()));
         }
+        if Popup::is_id_open(ctx, self.popup) {
+            above_parent(ctx, button.layer_id, egui::LayerId::new(egui::Order::Foreground, self.popup));
+        }
     }
 }
 

crates/ui-egui/src/widgets.rs

@@ -740,7 +740,9 @@ pub fn popup_value_field(ui: &mut Ui, name: &str, value: &mut f32, range: std::o
         ui.painter().rect_filled(arrow, t.radius_sm, t.field_border.gamma_multiply(0.6));
     }
     chevron_icon(ui, arrow, ui.style().interact(&resp), open);
+    let parent_layer = resp.layer_id;
     popup.show(|ui| {
+        crate::press_menu::above_parent_ui(parent_layer, ui);
         ui.set_width(POPUP_SLIDER_W);
         let s = slider(ui, value, range, None);
         s.widget_info(|| egui::WidgetInfo::slider(ui.is_enabled(), f64::from(*value), &name));
@@ -1666,6 +1668,7 @@ pub fn swatch_popup(swatch: &Response) -> egui::Popup<'static> {
         ctx.data_mut(|d| d.remove::<f32>(key));
         return popup;
     }
+    crate::press_menu::above_parent(ctx, swatch.layer_id, egui::LayerId::new(egui::Order::Foreground, popup.get_id()));
     // Its width is known from the frame after it opened (egui sizes it unseen first).
     let left = ctx.data(|d| d.get_temp::<f32>(key)).or_else(|| {
         let width = popup.get_expected_size()?.x;