Ticket #37980: 37980.2.diff

src/wp-admin/css/customize-controls.css

@@ -365 +365 @@
         display: block;
 }
 
-.panel-meta.customize-info .accordion-section-title {
+#customize-controls .panel-meta.customize-info .accordion-section-title {
         margin-left: 48px;
+        border-left: none;
 }
 
-#customize-controls .panel-meta.customize-info .accordion-section-title:hover {
+#customize-controls .panel-meta.customize-info .accordion-section-title:hover,
+#customize-controls .cannot-expand:hover .accordion-section-title {
         background: #fff;
         color: #555;
-        border-left: none;
+        border-left-color: #fff;
 }
 
 .customize-controls-close:focus,

src/wp-admin/js/customize-controls.js

@@ -614 +614 @@
                 attachEvents: function () {
                         var section = this;
 
+                        if ( section.container.hasClass( 'cannot-expand' ) ) {
+                                return;
+                        }
+
                         // Expand/Collapse accordion sections on click.
                         section.container.find( '.accordion-section-title, .customize-section-back' ).on( 'click keydown', function( event ) {
                                 if ( api.utils.isKeydownButNotEnterEvent( event ) ) {