Fix #316: the section eye stays while the pointer is on it

The eye was drawn only while the header itself was hovered; with the
pointer on the eye, egui reports the eye (on top) as hovered and not the
header, so the eye vanished under the pointer and could not be clicked.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01912WaK6Rmew3wxZuPyX7E8

crates/ui-egui/src/widgets.rs

@@ -270,8 +270,11 @@ pub fn section_header(ui: &mut Ui, id: &str, title: &str, open: bool, enabled: O
     paint(p, chev, if open { Icon::ChevronDown } else { Icon::ChevronRight }, t.text_label);
     p.text(pos2(r.left() + 44.0, r.center().y), Align2::LEFT_CENTER, title, t.semibold(14.0), t.text);
     let mut toggled = None;
+    // shown while the pointer is anywhere on the header: `resp.hovered()` turns false as soon as the
+    // pointer is over the eye itself (the eye is on top), which hid the eye before it could be
+    // clicked (issue #316)
     if let Some(on) = enabled
-        && (resp.hovered() || !on)
+        && (ui.rect_contains_pointer(r) || !on)
     {
         let eye = Rect::from_center_size(pos2(r.right() - 34.0, r.center().y), vec2(18.0, 18.0));
         let er = ui.interact(eye, ui.id().with(("eye", id)), Sense::click());