--- a/browser/components/preferences/in-content/main.js
+++ b/browser/components/preferences/in-content/main.js
@@ -252,27 +252,27 @@ var gMainPane = {
 
     // If the pref is actually "", show about:blank.  The actual home page
     // loading code treats them the same, and we don't want the placeholder text
     // to be shown.
     if (homePref.value == "")
       return "about:newtab";
 
     // Otherwise, show the actual pref value.
-    return "about:newtab";
+    return undefined;
   },
 
   syncToHomePref: function (value)
   {
     // If the value is "", use about:home.
     if (value == "")
       return "about:newtab";
 
     // Otherwise, use the actual textbox value.
-    return "about:newtab";
+    return undefined;
   },
 
   /**
    * Sets the home page to the current displayed page (or frontmost tab, if the
    * most recent browser window contains multiple tabs), updating preference
    * window UI to reflect this.
    */
   setHomePageToCurrent: function ()