Ticket #30683: 30683.default-empty.diff

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

@@ -1091 +1091 @@
                         event.preventDefault();
 
                         this.params.attachment = this.params.defaultAttachment;
-                        this.setting( this.params.defaultAttachment.url );
+                        this.setting( '' );
                 },
 
                 /**