--- a/browser/components/nsBrowserContentHandler.js
+++ b/browser/components/nsBrowserContentHandler.js
@@ -725,18 +725,19 @@ nsBrowserContentHandler.prototype = {
 };
 var gBrowserContentHandler = new nsBrowserContentHandler();
 
 function handURIToExistingBrowser(uri, location, cmdLine)
 {
   if (!shouldLoadURI(uri))
     return;
 
-  // Do not open external links in private windows
-  var navWin = RecentWindow.getMostRecentBrowserWindow({private: false});
+  // Do not open external links in private windows, unless we're in perma-private mode
+  var allowPrivate = PrivateBrowsingUtils.permanentPrivateBrowsing;
+  var navWin = RecentWindow.getMostRecentBrowserWindow({private: allowPrivate});
   if (!navWin) {
     // if we couldn't load it in an existing window, open a new one
     openWindow(null, gBrowserContentHandler.chromeURL, "_blank",
                "chrome,dialog=no,all" + gBrowserContentHandler.getFeatures(cmdLine),
                uri.spec);
     return;
   }