ui-egui: a click that opens the colour picker no longer closes it in the same frame (#1476)

crates/ui-egui/src/color_picker.rs

@@ -45,7 +45,13 @@ pub fn color_popup(ui: &mut Ui, id: egui::Id, pos: egui::Pos2, c: &mut [f32; 3])
     if ui.input_mut(|i| i.consume_key(egui::Modifiers::NONE, egui::Key::Escape)) {
         out.close = Some(false);
     }
-    if pressed_outside(ui.ctx(), &area.response) {
+    // A press in the pass that first draws the picker must not close it: an Area's rect is only
+    // at its requested position from its second pass on (the first pass reports it at the
+    // origin), so the click that just opened the picker would be read as a press outside it and
+    // the picker would flash and close in that one frame (#1476).
+    let pass_id = id.with("open-pass");
+    let drawn_before = ui.data(|d| d.get_temp::<u64>(pass_id)).is_some_and(|p| p < ui.ctx().cumulative_pass_nr());
+    if drawn_before && pressed_outside(ui.ctx(), &area.response) {
         out.close.get_or_insert(true);
     }
     if let Some(keep) = out.close {
@@ -56,13 +62,17 @@ pub fn color_popup(ui: &mut Ui, id: egui::Id, pos: egui::Pos2, c: &mut [f32; 3])
         ui.data_mut(|d| {
             d.insert_temp(id.with("open"), false);
             d.remove::<[f32; 3]>(orig_id);
+            d.remove::<u64>(pass_id);
             // Closed: the next Escape is the dialog's again.
             d.remove::<u64>(open_pass_id());
         });
     } else {
         // Still open after this pass: dialogs leave Escape to the picker (see `open_recently`).
         let pass = ui.ctx().cumulative_pass_nr();
-        ui.data_mut(|d| d.insert_temp(open_pass_id(), pass));
+        ui.data_mut(|d| {
+            d.insert_temp(pass_id, pass);
+            d.insert_temp(open_pass_id(), pass);
+        });
     }
     out.changed
 }

crates/ui-egui/tests/ui_color_hex.rs

@@ -114,6 +114,32 @@ fn is_open(h: &Harness<'_, [f32; 3]>) -> bool {
     h.query_by_role_and_label(Role::TextInput, "#").is_some()
 }
 
+/// #1476: the click that opens the picker must not close it. The picker's area only reports its
+/// real position from its second pass — on the pass it first draws, its rect is at the origin —
+/// so a click on a swatch outside that stale rect was read as a press outside the popup and the
+/// picker flashed and closed in the frame it opened.
+#[test]
+fn a_click_that_opens_the_picker_does_not_close_it_in_the_same_frame() {
+    let mut h = Harness::builder().with_size(vec2(560.0, 400.0)).build_ui_state(
+        |ui, c: &mut [f32; 3]| {
+            // Away from the top-left corner: the stale first-pass rect covers it.
+            ui.allocate_space(vec2(440.0, 120.0));
+            ui.horizontal(|ui| {
+                ui.add_space(440.0);
+                widgets::srgb_color_button(ui, c);
+            });
+        },
+        [1.0, 0.0, 0.0],
+    );
+    h.run_steps(2);
+    let button = h.get_by_role(Role::ColorWell).rect().center();
+    h.input_mut().events.push(Event::PointerMoved(button));
+    h.input_mut().events.push(Event::PointerButton { pos: button, button: egui::PointerButton::Primary, pressed: true, modifiers: Modifiers::NONE });
+    h.input_mut().events.push(Event::PointerButton { pos: button, button: egui::PointerButton::Primary, pressed: false, modifiers: Modifiers::NONE });
+    h.run_steps(2);
+    assert!(is_open(&h), "the click that opens the picker must not close it");
+}
+
 #[test]
 fn the_dialog_colour_button_stores_srgb() {
     let mut h = picker([1.0, 1.0, 1.0]);