--- a/browser/components/search/content/search.xml
+++ b/browser/components/search/content/search.xml
@@ -500,25 +500,25 @@
 #endif
               where = "tab-background";
           }
 
           let selection = this.telemetrySearchDetails;
           this.doSearch(textValue, where, aEngine);
 
           if (!selection || (selection.index == -1)) {
-            let target = aEvent.originalTarget;
             let source = "unknown";
             let type = "unknown";
             if (aEvent instanceof KeyboardEvent) {
               type = "key";
               if (this._textbox.getSelectedOneOff()) {
                 source = "oneoff";
               }
             } else if (aEvent instanceof MouseEvent) {
+              let target = aEvent.originalTarget;
               type = "mouse";
               if (target.classList.contains("searchbar-engine-one-off-item")) {
                 source = "oneoff";
               } else if (target.classList.contains("search-panel-header") ||
                          target.parentNode.classList.contains("search-panel-header")) {
                 source = "header";
               }
             }