Ticket #29983: 29983.2.diff

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

@@ -1624 +1624 @@
                                 widgetNumber = parsedWidgetId.number,
                                 widgetIdBase = parsedWidgetId.id_base,
                                 widget = api.Widgets.availableWidgets.findWhere( {id_base: widgetIdBase} ),
-                                settingId, isExistingWidget, widgetFormControl, sidebarWidgets, settingArgs;
+                                settingId, isExistingWidget, widgetFormControl, sidebarWidgets, settingArgs, setting;
 
                         if ( ! widget ) {
                                 return false;
@@ -1683 +1683 @@
                                         transport: 'refresh',
                                         previewer: this.setting.previewer
                                 };
-                                api.create( settingId, settingId, {}, settingArgs );
+                                setting = api.create( settingId, settingId, '', settingArgs );
+                                setting.set( {} ); // mark dirty, changing from '' to {}
                         }
 
                         controlConstructor = api.controlConstructor[controlType];