fix(ui): menu items highlight under the pointer (#1174)

The cell and header right-click menus, the ribbon dropdown menus and the data
validation pick list drew their items with Button::frame(false), which turns
the background off in every state, hover included. frame_when_inactive(false)
keeps them flat at rest and shows the hover background, as Excel's menus do.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/ui-egui/src/grid.rs

@@ -2879,7 +2879,7 @@ fn context_menu(app: &mut SheetApp, ui: &mut egui::Ui) {
                     ui.separator();
                     continue;
                 }
-                if ui.add(egui::Button::new(lang.tr(label)).frame(false).min_size(vec2(190.0, 20.0))).clicked() {
+                if ui.add(egui::Button::new(lang.tr(label)).frame_when_inactive(false).min_size(vec2(190.0, 20.0))).clicked() {
                     close = true;
                     match id {
                         "ui:pasteSpecial" => app.open_dialog("pasteSpecial", json!({})),
@@ -3088,7 +3088,7 @@ fn list_picker(app: &mut SheetApp, ui: &mut egui::Ui, geo: &Geo, was_open: bool)
             ui.set_min_width(r.width().max(100.0));
             egui::ScrollArea::vertical().max_height(200.0).show(ui, |ui| {
                 for it in &items {
-                    if ui.add(egui::Button::new(it.as_str()).frame(false).min_size(vec2(r.width().max(100.0), 18.0))).clicked() {
+                    if ui.add(egui::Button::new(it.as_str()).frame_when_inactive(false).min_size(vec2(r.width().max(100.0), 18.0))).clicked() {
                         app.run_or_alert("cell.set", json!({"cell": c.a1(), "input": it}));
                         close = true;
                     }
@@ -3151,7 +3151,7 @@ fn header_menu(app: &mut SheetApp, ui: &mut egui::Ui, was_open: bool) {
                     ui.separator();
                     continue;
                 }
-                if ui.add(egui::Button::new(lang.tr(label)).frame(false).min_size(vec2(180.0, 20.0))).clicked() {
+                if ui.add(egui::Button::new(lang.tr(label)).frame_when_inactive(false).min_size(vec2(180.0, 20.0))).clicked() {
                     close = true;
                     match id {
                         "ui:insertPaste" => app.open_dialog("insertPaste", json!({})),

crates/ui-egui/src/ribbon.rs

@@ -485,7 +485,7 @@ fn menu_items(app: &mut SheetApp, ui: &mut Ui, items: &[(&str, &str, serde_json:
             continue;
         }
         let lang = app.ui.language;
-        let response = ui.add(egui::Button::new(lang.tr(label)).frame(false).min_size(vec2(220.0, 22.0)));
+        let response = ui.add(egui::Button::new(lang.tr(label)).frame_when_inactive(false).min_size(vec2(220.0, 22.0)));
         if let Some(sequence) = keytip_table::item_letter(app.keytips.prefix().unwrap_or_default(), id) {
             keytip(app, ui, sequence, pos2(response.rect.right() - 10.0, response.rect.center().y));
         }

crates/ui-egui/tests/menu_hover.rs

@@ -0,0 +1,71 @@
+//! Menu items highlight under the pointer, as in Excel (#1174): no background at rest, the hover
+//! background while the pointer is on an item.
+
+use egui::{Event, Modifiers, PointerButton, Pos2, Shape, accesskit::Role};
+use egui_kittest::kittest::Queryable as _;
+use gridcraft_engine::Session;
+use gridcraft_engine::core::CellRef;
+use gridcraft_ui_egui::{SheetApp, grid};
+
+type Harness = egui_kittest::Harness<'static, SheetApp>;
+
+fn harness() -> Harness {
+    let mut s = Session::new();
+    s.new_workbook();
+    let mut h = egui_kittest::Harness::builder().with_size(egui::vec2(1200.0, 800.0)).build_ui_state(
+        |ui, app: &mut SheetApp| {
+            app.logic(ui.ctx());
+            app.ui(ui);
+        },
+        SheetApp::new(s, Default::default()),
+    );
+    h.run_steps(4);
+    h
+}
+
+fn cell_center(h: &Harness, cell: &str) -> egui::Rect {
+    let app = h.state();
+    let sh = app.session.active().unwrap().wb.active().unwrap();
+    let geo = grid::Geo::new(sh, app.grid.rect.unwrap(), app.view().scroll);
+    geo.cell_rect(sh, CellRef::parse(cell).unwrap())
+}
+
+fn right_click(h: &mut Harness, pos: Pos2) {
+    h.input_mut().events.push(Event::PointerMoved(pos));
+    for pressed in [true, false] {
+        h.input_mut().events.push(Event::PointerButton { pos, button: PointerButton::Secondary, pressed, modifiers: Modifiers::NONE });
+        h.run_steps(2);
+    }
+}
+
+/// Is a filled rectangle in the hovered-widget colour painted under `at`?
+fn hover_fill_under(h: &Harness, at: Pos2) -> bool {
+    let fill = h.ctx.global_style().visuals.widgets.hovered.weak_bg_fill;
+    h.output().shapes.iter().any(|s| matches!(&s.shape, Shape::Rect(r) if r.fill == fill && r.rect.contains(at)))
+}
+
+fn check_item(h: &mut Harness, label: &str) {
+    let at = h.get_by_role_and_label(Role::Button, label).rect().center();
+    assert!(!hover_fill_under(h, at), "{label} has no background before the pointer is on it");
+    h.input_mut().events.push(Event::PointerMoved(at));
+    h.run_steps(2);
+    assert!(hover_fill_under(h, at), "{label} is highlighted under the pointer");
+}
+
+#[test]
+fn cell_menu_items_highlight_under_the_pointer() {
+    let mut h = harness();
+    let pos = cell_center(&h, "C5").center();
+    right_click(&mut h, pos);
+    assert!(h.state().grid.context_menu.is_some());
+    check_item(&mut h, "Copy");
+}
+
+#[test]
+fn header_menu_items_highlight_under_the_pointer() {
+    let mut h = harness();
+    let c1 = cell_center(&h, "C1");
+    right_click(&mut h, egui::pos2(c1.center().x, c1.top() - 6.0));
+    assert!(h.state().grid.header_menu.is_some());
+    check_item(&mut h, "Copy");
+}