FIX: iOS/iPadOS freezing when changing notification level in topic footer

app/assets/stylesheets/common/select-kit/topic-notifications-button.scss

@@ -16,3 +16,15 @@
     }
   }
 }
+
+// This is a weird fix for a weird issue in iOS/iPadOS, the browser freezes
+// when changing the notification level while in the fullscreen topic footer.
+// This prevents the selected option icon from being hidden while saving,
+// and somehow that makes Safari happy.
+.timeline-fullscreen {
+  .topic-notifications-button.is-loading {
+    .selected-name .d-icon {
+      display: inline-flex;
+    }
+  }
+}