Ticket #30859: 30859.patch

src/wp-admin/js/tags-box.js

@@ -109 +109 @@
                                 newtag = $( 'input.newtag', el ),
                                 comma = window.tagsBoxL10n.tagDelimiter;
 
+                        // Tags aren't editable, flush not required
+                        if ( ! newtag.length ) {
+                                return;
+                        }
+
                         a = a || false;
 
                         text = a ? $(a).text() : newtag.val();