Ticket #56830: 56830.3.diff

src/js/_enqueues/lib/dialog.js

@@ -17 +17 @@
                         this._super();
 
                         // WebKit leaves focus in the TinyMCE editor unless we shift focus.
-                        this.element._trigger('focus');
+                        this.element.trigger('focus');  
                         this._trigger('refresh');
                 }
         });