Layers panel: right-click opens the fx and adjustment footer menus (#1680)

As in Photoshop, a secondary click on the Layers footer's Add a layer style and Create new fill or
adjustment layer buttons opens their menus too (a primary click still toggles them), and a small
arrow marks them as menu buttons. Fixes #1579.

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

crates/ui-egui/src/panels.rs

@@ -1606,8 +1606,8 @@ fn layers(app: &mut PhotocraftApp, ui: &mut egui::Ui) {
                 actions.push(("layer.new.group".into(), json!({})));
             }
             actions.extend(footer_drop(ui, &group, footer_drag, "layer.groupLayers"));
-            let adj = icons::button(ui, "contrast", 26.0, false, tl!("Create new fill or adjustment layer"));
-            egui::Popup::menu(&adj).show(|ui| {
+            let adj = footer_menu_button(ui, "contrast", 26.0, tl!("Create new fill or adjustment layer"));
+            egui::Popup::menu(&adj).open_memory(footer_menu_right_click(&adj)).show(|ui| {
                 ui.set_min_width(190.0);
                 for c in photocraft_engine::command_specs().iter().filter(|c| c.id.starts_with("layer.newAdjustmentLayer.")) {
                     if ui.button(tl!(c.label).trim_end_matches('…')).clicked() {
@@ -1638,7 +1638,7 @@ fn layers(app: &mut PhotocraftApp, ui: &mut egui::Ui) {
                 actions.push((crate::layer_menu_ui::add_mask_command(doc.selection.is_some(), alt).into(), json!({})));
             }
             let fx = fx_button(ui, 26.0, tl!("Add a layer style"));
-            egui::Popup::menu(&fx).show(|ui| {
+            egui::Popup::menu(&fx).open_memory(footer_menu_right_click(&fx)).show(|ui| {
                 ui.set_min_width(180.0);
                 if ui.button(tl!("Blending Options…")).clicked() {
                     crate::layer_style::open(app, None);
@@ -1711,6 +1711,31 @@ fn footer_label(command: &str) -> &'static str {
     }
 }
 
+/// A secondary click opens a Layers footer popup, as in Photoshop; a primary click still toggles
+/// it (the `Popup::menu` default this replaces).
+fn footer_menu_right_click(response: &egui::Response) -> Option<egui::SetOpenCommand> {
+    if response.secondary_clicked() {
+        Some(egui::SetOpenCommand::Bool(true))
+    } else if response.clicked() {
+        Some(egui::SetOpenCommand::Toggle)
+    } else {
+        None
+    }
+}
+
+/// The small down-arrow makes it clear that the footer icon expands into a menu.
+fn footer_menu_arrow(ui: &egui::Ui, rect: Rect) {
+    let t = Tokens::get(ui.ctx());
+    let arrow = Rect::from_min_size(rect.right_bottom() - vec2(11.0, 10.0), vec2(9.0, 9.0));
+    icons::paint(ui, arrow, "chevron-down", 8.0, t.text_dim);
+}
+
+fn footer_menu_button(ui: &mut egui::Ui, icon: &str, size: f32, tip: &str) -> egui::Response {
+    let response = icons::button(ui, icon, size, false, tip);
+    footer_menu_arrow(ui, response.rect);
+    response
+}
+
 /// Photoshop's italic "fx" footer button (no icon-font equivalent).
 fn fx_button(ui: &mut egui::Ui, size: f32, tip: &str) -> egui::Response {
     let t = Tokens::get(ui.ctx());
@@ -1722,6 +1747,7 @@ fn fx_button(ui: &mut egui::Ui, size: f32, tip: &str) -> egui::Response {
     job.append("fx", 0.0, egui::TextFormat { font_id: egui::FontId::proportional(15.0), color: t.icon, italics: true, ..Default::default() });
     let g = ui.painter().layout_job(job);
     ui.painter().galley(r.center() - g.size() / 2.0, g, t.icon);
+    footer_menu_arrow(ui, r);
     resp.on_hover_text(tip)
 }
 
@@ -3433,6 +3459,48 @@ mod layer_drag_edge_scroll_tests {
     }
 }
 
+#[cfg(test)]
+mod footer_menu_tests {
+    use super::*;
+
+    // Exercise the actual egui pointer path, not just a mocked click flag.
+    #[test]
+    fn right_click_opens_footer_menu_and_primary_click_still_works() {
+        let ctx = egui::Context::default();
+        let rect = Rect::from_min_size(Pos2::ZERO, vec2(300.0, 100.0));
+        let pos = pos2(35.0, 20.0);
+        let frame = |events: Vec<egui::Event>| {
+            let mut opened = false;
+            let mut output = ctx.run_ui(egui::RawInput { screen_rect: Some(rect), events, ..Default::default() }, |ui| {
+                let response = ui.add_sized([100.0, 28.0], egui::Button::new("Footer menu"));
+                egui::Popup::menu(&response).open_memory(footer_menu_right_click(&response)).show(|ui| {
+                    opened = true;
+                    ui.label("Menu entry");
+                });
+            });
+            output.textures_delta.clear();
+            opened
+        };
+        frame(Vec::new());
+        frame(vec![
+            egui::Event::PointerMoved(pos),
+            egui::Event::PointerButton { pos, button: egui::PointerButton::Secondary, pressed: true, modifiers: egui::Modifiers::NONE },
+        ]);
+        assert!(
+            frame(vec![egui::Event::PointerButton { pos, button: egui::PointerButton::Secondary, pressed: false, modifiers: egui::Modifiers::NONE }]),
+            "secondary release opens the popup"
+        );
+
+        // A primary click also remains supported by egui::Popup::menu.
+        frame(vec![egui::Event::Key { key: egui::Key::Escape, physical_key: None, pressed: true, repeat: false, modifiers: egui::Modifiers::NONE }]);
+        frame(vec![egui::Event::PointerButton { pos, button: egui::PointerButton::Primary, pressed: true, modifiers: egui::Modifiers::NONE }]);
+        assert!(
+            frame(vec![egui::Event::PointerButton { pos, button: egui::PointerButton::Primary, pressed: false, modifiers: egui::Modifiers::NONE }]),
+            "primary release still opens the popup"
+        );
+    }
+}
+
 #[cfg(test)]
 mod group_drag_selection_tests {
     use super::*;