FIX: Add button only if it doesn't exist

src/core/js/ext_bookmarks.js

@@ -569,7 +569,12 @@ var ext_bookmarks = function ($, logger, config) {
      * Add a button to add all query results to bookmarks.
      */
     const add_add_query_results_button = function () {
-        const button_html = $(`<div class="row"><p class="text-end">Bookmark all query results</p></div>`)[0];
+        const row_id = "caosdb-add-query-to-bookmarks-row"
+        // do nothing if already existing
+        if ($("#" + row_id).length > 0) {
+            return;
+        }
+        const button_html = $(`<div class="row" id=${row_id}><p class="text-end">Bookmark all query results</p></div>`)[0];
 
         // Add to query results box
         $(".caosdb-query-response-heading").append(button_html);