Fix #316: the header keeps its hover shade while the pointer is on the eye

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01912WaK6Rmew3wxZuPyX7E8

crates/ui-egui/src/widgets.rs

@@ -263,7 +263,7 @@ pub fn section_header(ui: &mut Ui, id: &str, title: &str, open: bool, enabled: O
     resp.widget_info(|| egui::WidgetInfo::selected(egui::WidgetType::CollapsingHeader, true, open, title));
     register(ui.ctx(), format!("section:{id}"), r);
     let p = ui.painter();
-    if resp.hovered() {
+    if ui.rect_contains_pointer(r) {
         p.rect_filled(r, 0.0, t.chrome.gamma_multiply(1.06));
     }
     let chev = Rect::from_center_size(pos2(r.left() + 30.0, r.center().y), vec2(14.0, 14.0));