--- a/browser/components/search/content/search.xml
+++ b/browser/components/search/content/search.xml
@@ -2119,17 +2119,17 @@
       </method>
 
     </implementation>
 
     <handlers>
 
       <handler event="mousedown"><![CDATA[
         let target = event.originalTarget;
-        if (!target.classList.contains("searchbar-engine-one-off-item")) {
+        if (target.getAttribute("anonid") == "addengine-menu-button") {
           return;
         }
         // Required to receive click events from the buttons on Linux.
         event.preventDefault();
       ]]></handler>
 
       <handler event="mousemove"><![CDATA[
         let target = event.originalTarget;