--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -1612,17 +1612,17 @@ var gBrowserInit = {
 
     let mm = window.messageManager;
     mm.addMessageListener("Browser:FirstPaint", function onFirstPaint() {
       mm.removeMessageListener("Browser:FirstPaint", onFirstPaint);
       firstBrowserPaintDeferred.resolve();
     });
 
     this._uriToLoadPromise.then(uriToLoad => {
-      if (!uriToLoad || uriToLoad == "about:blank") {
+      if (!uriToLoad) {
         return;
       }
 
       // We don't check if uriToLoad is a XULElement because this case has
       // already been handled before first paint, and the argument cleared.
       if (uriToLoad instanceof Ci.nsIArray) {
         let count = uriToLoad.length;
         let specs = [];

--- a/browser/base/content/tabbrowser.xml
+++ b/browser/base/content/tabbrowser.xml
@@ -23,16 +23,17 @@
                   onselect="if (event.target.localName == 'tabpanels') this.parentNode.updateCurrentBrowser();">
         <xul:tabpanels flex="1" class="plain" selectedIndex="0" anonid="panelcontainer">
           <xul:notificationbox flex="1" notificationside="top">
             <xul:hbox flex="1" class="browserSidebarContainer">
               <xul:vbox flex="1" class="browserContainer">
                 <xul:stack flex="1" class="browserStack" anonid="browserStack">
                   <xul:browser anonid="initialBrowser" type="content" message="true" messagemanagergroup="browsers"
                                primary="true"
+                               nodefaultsrc="true"
                                xbl:inherits="tooltip=contenttooltip,contextmenu=contentcontextmenu,autocompletepopup,selectmenulist,datetimepicker"/>
                 </xul:stack>
               </xul:vbox>
             </xul:hbox>
           </xul:notificationbox>
         </xul:tabpanels>
       </xul:tabbox>
       <children/>