--- a/toolkit/components/search/nsSearchService.js
+++ b/toolkit/components/search/nsSearchService.js
@@ -4031,16 +4031,19 @@ SearchService.prototype = {
       FAIL("Invalid template passed to addEngineWithDetails!");
     if (this._engines[aName])
       FAIL("An engine with that name already exists!", Cr.NS_ERROR_FILE_ALREADY_EXISTS);
 
     var engine = new Engine(sanitizeName(aName), false);
     engine._initFromMetadata(aName, aIconURL, aAlias, aDescription,
                              aMethod, aTemplate, aExtensionID);
     engine._loadPath = "[other]addEngineWithDetails";
+    if (aExtensionID) {
+      engine._loadPath += ":" + aExtensionID;
+    }
     this._addEngineToStore(engine);
   },
 
   addEngine: function SRCH_SVC_addEngine(aEngineURL, aDataType, aIconURL,
                                          aConfirm, aCallback) {
     LOG("addEngine: Adding \"" + aEngineURL + "\".");
     this._ensureInitialized();
     try {