Ticket #37216: 37216.diff

src/wp-admin/js/updates.js

@@ -886 +886 @@
                 wp.a11y.speak( wp.updates.l10n.updatingMsg, 'polite' );
                 $notice.text( wp.updates.l10n.updating );
 
+                $document.trigger( 'wp-theme-updating' );
+
                 return wp.updates.ajax( 'update-theme', args );
         };