Option lists occlude: a wheel over the / menu, or any floating list, scrolled the page behind it too (#12)

src/forms/options.rs

@@ -321,6 +321,7 @@ impl Popup<'_> {
             })
             .max_w(window.viewport_size().width - theme.window_margin() * 2.0)
             .max_h(theme.list_max_height())
+            .occlude()
             .overflow_y_scroll()
             .when_some(self.scroll, |list, handle| list.track_scroll(handle))
             .p_1()

src/forms/tests/mod.rs

@@ -2,6 +2,7 @@ mod choices;
 mod colors;
 mod dates;
 mod other;
+mod popup;
 mod stale;
 mod structure;
 mod tags;

src/forms/tests/popup.rs

@@ -0,0 +1,50 @@
+use gpui::{
+    Context, IntoElement, KeyUpEvent, Keystroke, Modifiers, ParentElement, Render, ScrollDelta,
+    ScrollHandle, ScrollWheelEvent, Styled, TestAppContext, TouchPhase, Window, div, point,
+    prelude::*, px,
+};
+
+use super::setup;
+use crate::forms::{Choice, Select};
+
+/// A long select at the top of a page that scrolls.
+struct Page(ScrollHandle);
+
+impl Render for Page {
+    fn render(&mut self, _: &mut Window, _: &mut Context<Self>) -> impl IntoElement {
+        let choices = (0..40).map(|ix| Choice::new(format!("{ix}"), format!("Choice {ix}")));
+        div()
+            .id("page")
+            .size_full()
+            .overflow_y_scroll()
+            .track_scroll(&self.0)
+            .child(div().w(px(200.0)).child(Select::new("long", choices)))
+            .child(div().h(px(2000.0)))
+    }
+}
+
+#[gpui::test]
+fn a_wheel_over_an_open_list_leaves_the_page(cx: &mut TestAppContext) {
+    setup(cx);
+    let page = ScrollHandle::new();
+    let (_, cx) = cx.add_window_view({
+        let page = page.clone();
+        |_, _| Page(page)
+    });
+    cx.run_until_parked();
+    cx.update(|window, cx| window.focus_next(cx));
+    cx.simulate_keystrokes("enter");
+    cx.simulate_event(KeyUpEvent {
+        keystroke: Keystroke::parse("enter").unwrap(),
+    });
+    cx.run_until_parked();
+    let list = cx.debug_bounds("option-list").expect("the list opens");
+    cx.simulate_event(ScrollWheelEvent {
+        position: list.center(),
+        delta: ScrollDelta::Pixels(point(px(0.0), px(-120.0))),
+        modifiers: Modifiers::none(),
+        touch_phase: TouchPhase::Moved,
+    });
+    cx.run_until_parked();
+    assert_eq!(page.offset().y, px(0.0), "the page stayed");
+}