fix weird expansion of top bar when hovering notification container, fixes #4698

Closes #4698

Merge request studip/studip!3493

resources/assets/stylesheets/scss/personal-notifications.scss

@@ -41,6 +41,10 @@
         left: (-$list-width);
         right: 0;
         height: $arrow-height;
+
+        // The following transformations eliminates a bug that would expand
+        // the #top-bar when the container is hovered
+        transform: translate3d(0, 0, 0);
     }
     &:hover::after {
         content: "";