Ticket #31687: 31687.1.diff

wp-admin/js/customize-controls.js

@@ -1929 +1929 @@
 
                         this.query = $.extend( params.query || {}, { customize_messenger_channel: this.channel() });
 
+                        // This avoids SecurityErrors when setting a window object in x-origin iframe'd scenarios
+                        this.targetWindow.set = function( to ) {
+                                var from = this._value;
+
+                                to = this._setter.apply( this, arguments );
+                                to = this.validate( to );
+
+                                if ( null === to || from === to ) {
+                                        return this;
+                                }
+
+                                this._value = to;
+                                this._dirty = true;
+
+                                this.callbacks.fireWith( this, [ to, from ] );
+
+                                return this;
+                        };
+
                         this.run( deferred );
                 },