diff --git a/components/domain-isolator.js b/components/domain-isolator.js
index e04005a5..891a19cc 100644
--- a/components/domain-isolator.js
+++ b/components/domain-isolator.js
@@ -173,7 +173,7 @@ function DomainIsolator() {
 
 // Firefox component requirements
 DomainIsolator.prototype = {
-  QueryInterface: ChromeUtils.generateQI([Ci.nsISupports, Ci.nsIObserver]),
+  QueryInterface: ChromeUtils.generateQI([Ci.nsIObserver]),
   classDescription: kMODULE_NAME,
   classID: kMODULE_CID,
   contractID: kMODULE_CONTRACTID,
diff --git a/components/dragDropFilter.js b/components/dragDropFilter.js
index 4465187e..66dbe3a4 100644
--- a/components/dragDropFilter.js
+++ b/components/dragDropFilter.js
@@ -32,7 +32,7 @@ function DragDropFilter() {
 
 DragDropFilter.prototype =
 {
-  QueryInterface: ChromeUtils.generateQI([Ci.nsISupports, Ci.nsIObserver]),
+  QueryInterface: ChromeUtils.generateQI([Ci.nsIObserver]),
 
   // make this an nsIClassInfo object
   flags: Ci.nsIClassInfo.DOM_OBJECT,
diff --git a/components/external-app-blocker.js b/components/external-app-blocker.js
index 747824d1..1cc2000f 100644
--- a/components/external-app-blocker.js
+++ b/components/external-app-blocker.js
@@ -33,7 +33,7 @@ ExternalAppBlocker.prototype =
 {
   _helperAppLauncher: undefined,
 
-  QueryInterface: ChromeUtils.generateQI([Ci.nsISupports, Ci.nsIObserver,
+  QueryInterface: ChromeUtils.generateQI([Ci.nsIObserver,
                                          Ci.nsIHelperAppWarningDialog]),
 
   // make this an nsIClassInfo object
diff --git a/components/torCheckService.js b/components/torCheckService.js
index 4f79bef4..d4815ee2 100644
--- a/components/torCheckService.js
+++ b/components/torCheckService.js
@@ -25,7 +25,7 @@ function TBTorCheckService() {
 
 TBTorCheckService.prototype =
 {
-  QueryInterface: ChromeUtils.generateQI([Ci.nsISupports, Ci.nsIClassInfo]),
+  QueryInterface: ChromeUtils.generateQI([Ci.nsIClassInfo]),
 
   kCheckNotInitiated: 0, // Possible values for statusOfTorCheck.
   kCheckSuccessful: 1,
diff --git a/components/torbutton-logger.js b/components/torbutton-logger.js
index ce4ba70b..22c664fa 100644
--- a/components/torbutton-logger.js
+++ b/components/torbutton-logger.js
@@ -58,7 +58,7 @@ function padInt(i)
 
 TorbuttonLogger.prototype =
 {
-  QueryInterface: ChromeUtils.generateQI([Ci.nsISupports, Ci.nsIClassInfo]),
+  QueryInterface: ChromeUtils.generateQI([Ci.nsIClassInfo]),
 
   wrappedJSObject: null,  // Initialized by constructor