Data validation: hide the input message while the cell's list is open (#505)

The input message is a tooltip-order area just below the cell, and the in-cell
dropdown opens at the same spot, so the message covered the first items of the
list. It now stays hidden while the list picker is open on the active cell and
comes back when the list closes.

crates/ui-egui/src/grid.rs

@@ -2715,8 +2715,9 @@ pub(crate) fn paint_overlays(
         p.rect_stroke(r, 2.0, Stroke::new(1.0, Color32::from_gray(160)), StrokeKind::Inside);
         crate::icons::paint(p, r.shrink(3.0), crate::icons::Icon::Chevron, Color32::from_gray(60));
     }
-    // Input message of the active cell's validation.
+    // Input message of the active cell's validation, hidden while its list is open: it would cover the items.
     if app.editor.is_none()
+        && app.grid.list_picker != Some(sel.active)
         && let Some(dv) = sh.validations.iter().find(|d| d.ranges.iter().any(|r| r.contains(sel.active)))
         && dv.show_input
         && !(dv.input_title.is_empty() && dv.input_message.is_empty())

crates/ui-egui/tests/validation_input_message.rs

@@ -0,0 +1,56 @@
+//! A list validation's input message must not cover the dropdown it describes (#505).
+
+use egui::{Event, Key, Modifiers, PointerButton};
+use egui_kittest::kittest::Queryable;
+use gridcraft_engine::Session;
+use gridcraft_engine::core::CellRef;
+use gridcraft_ui_egui::{SheetApp, grid};
+use serde_json::json;
+
+type Harness = egui_kittest::Harness<'static, SheetApp>;
+
+const MESSAGE: &str = "Pick a colour from the list";
+
+fn harness() -> Harness {
+    let mut session = Session::new();
+    session.new_workbook();
+    session.execute("data.validation", json!({"range": "B2", "type": "list", "formula1": "\"Red,Green,Blue\"", "inputMessage": MESSAGE})).unwrap();
+    session.execute("selection.set", json!({"cell": "B2"})).unwrap();
+    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(session, Default::default()),
+    );
+    h.run_steps(4);
+    h
+}
+
+fn message_shown(h: &Harness) -> bool {
+    h.query_by_label(MESSAGE).is_some()
+}
+
+#[test]
+fn input_message_hides_while_the_list_is_open() {
+    let mut h = harness();
+    assert!(message_shown(&h), "the selected cell's input message is shown");
+
+    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);
+    let pos = grid::validation_arrow(sh, &geo, CellRef::parse("B2").unwrap()).unwrap().center();
+    h.input_mut().events.push(Event::PointerMoved(pos));
+    h.input_mut().events.push(Event::PointerButton { pos, button: PointerButton::Primary, pressed: true, modifiers: Modifiers::NONE });
+    h.input_mut().events.push(Event::PointerButton { pos, button: PointerButton::Primary, pressed: false, modifiers: Modifiers::NONE });
+    h.run_steps(2);
+
+    assert!(h.state().grid.list_picker.is_some(), "the dropdown arrow opens the list");
+    assert!(h.query_by_label("Green").is_some(), "the list shows its items");
+    assert!(!message_shown(&h), "the input message must not cover the open list");
+
+    h.input_mut().events.push(Event::Key { key: Key::Escape, physical_key: None, pressed: true, repeat: false, modifiers: Modifiers::NONE });
+    h.run_steps(2);
+    assert!(h.state().grid.list_picker.is_none(), "Escape closes the list");
+    assert!(message_shown(&h), "the input message comes back once the list is closed");
+}