diff --git a/chat/content/convbrowser.xml b/chat/content/convbrowser.xml
index 188cdedbcd..fcced410f8 100644
--- a/chat/content/convbrowser.xml
+++ b/chat/content/convbrowser.xml
@@ -209,9 +209,7 @@
           this.autoCopyEnabled = Services.clipboard.supportsSelectionClipboard() &&
             Services.prefs.getBoolPref("clipboard.autocopy");
           if (this.autoCopyEnabled) {
-            this.contentWindow.getSelection()
-                .QueryInterface(Ci.nsISelectionPrivate)
-                .addSelectionListener(this);
+            this.contentWindow.getSelection().addSelectionListener(this);
           }
           ]]>
         </body>
@@ -222,9 +220,7 @@
           <![CDATA[
           this.contentWindow.controllers.removeController(this);
           if (this.autoCopyEnabled) {
-             this.contentWindow.getSelection()
-                 .QueryInterface(Ci.nsISelectionPrivate)
-                 .removeSelectionListener(this);
+             this.contentWindow.getSelection().removeSelectionListener(this);
           }
           ]]>
         </body>
diff --git a/suite/browser/nsTypeAheadFind.js b/suite/browser/nsTypeAheadFind.js
index d3b4bafc27..15ff16215b 100644
--- a/suite/browser/nsTypeAheadFind.js
+++ b/suite/browser/nsTypeAheadFind.js
@@ -335,8 +335,7 @@ typeAheadFind.prototype = {
       this.mSelection = editable.editor.selection;
     else
       this.mSelection = commandDispatcher.focusedWindow.getSelection();
-    this.mSelection.QueryInterface(Ci.nsISelectionPrivate)
-                   .addSelectionListener(this);
+    this.mSelection.addSelectionListener(this);
     return false;
   },
   startFind: function(aWindow, aLinks) {
diff --git a/suite/extensions/debugQA/content/debugQAEditorOverlay.js b/suite/extensions/debugQA/content/debugQAEditorOverlay.js
index 481cf38f68..3183064363 100644
--- a/suite/extensions/debugQA/content/debugQAEditorOverlay.js
+++ b/suite/extensions/debugQA/content/debugQAEditorOverlay.js
@@ -49,7 +49,7 @@ function EditorTestSelection()
 
   dump("Selection contains:\n");
   // 3rd param = column to wrap
-  dump(selection.QueryInterface(Ci.nsISelectionPrivate)
+  dump(selection
        .toStringWithFormat("text/plain",
                            kOutputFormatted | kOutputSelectionOnly,
                            0) + "\n");