diff --git a/browser/base/content/browser.js b/browser/base/content/browser.js
index 43af50e5be3..517d127976d 100644
--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -4413,7 +4413,6 @@ var FullScreen = {
     // and in tabs-on-bottom mode, move them back to the navigation toolbar.
     // When there is a chance the tab bar may be collapsed, put window
     // controls on nav bar.
-    var fullscreenflex = document.getElementById("fullscreenflex");
     var fullscreenctls = document.getElementById("window-controls");
     var navbar = document.getElementById("nav-bar");
     var ctlsOnTabbar = window.toolbar.visible &&
@@ -4421,14 +4420,12 @@ var FullScreen = {
                           (TabsOnTop.enabled &&
                            !gPrefService.getBoolPref("browser.tabs.autoHide")));
     if (fullscreenctls.parentNode == navbar && ctlsOnTabbar) {
+      fullscreenctls.removeAttribute("flex");
       document.getElementById("TabsToolbar").appendChild(fullscreenctls);
-      // we don't need this space in tabs-on-top mode, so prevent it from 
-      // being shown
-      fullscreenflex.removeAttribute("fullscreencontrol");
     }
     else if (fullscreenctls.parentNode.id == "TabsToolbar" && !ctlsOnTabbar) {
+      fullscreenctls.setAttribute("flex", "1");
       navbar.appendChild(fullscreenctls);
-      fullscreenflex.setAttribute("fullscreencontrol", "true");
     }
 
     var controls = document.getElementsByAttribute("fullscreencontrol", "true");
diff --git a/browser/base/content/browser.xul b/browser/base/content/browser.xul
index a6549cfc3d8..a0c13684d48 100644
--- a/browser/base/content/browser.xul
+++ b/browser/base/content/browser.xul
@@ -475,7 +475,7 @@
              toolbarname="&navbarCmd.label;" accesskey="&navbarCmd.accesskey;"
              fullscreentoolbar="true" mode="icons" customizable="true"
              iconsize="large"
-             defaultset="unified-back-forward-button,urlbar-container,reload-button,stop-button,search-container,home-button,bookmarks-menu-button-container,fullscreenflex,window-controls"
+             defaultset="unified-back-forward-button,urlbar-container,reload-button,stop-button,search-container,home-button,bookmarks-menu-button-container,window-controls"
              context="toolbar-context-menu">
 
       <toolbaritem id="unified-back-forward-button" class="chromeclass-toolbar-additional"
@@ -697,8 +697,7 @@
         </toolbarbutton>
       </toolbaritem>
 
-      <hbox id="fullscreenflex" flex="1" hidden="true" fullscreencontrol="true"/>
-      <hbox id="window-controls" hidden="true" fullscreencontrol="true">
+      <hbox id="window-controls" hidden="true" fullscreencontrol="true" pack="end">
         <toolbarbutton id="minimize-button"
                        tooltiptext="&fullScreenMinimize.tooltip;"
                        oncommand="window.minimize();"/>
diff --git a/browser/components/nsBrowserGlue.js b/browser/components/nsBrowserGlue.js
index 26f20e9c3ec..dd1feb1cac1 100644
--- a/browser/components/nsBrowserGlue.js
+++ b/browser/components/nsBrowserGlue.js
@@ -1243,13 +1243,7 @@ BrowserGlue.prototype = {
       // Need to migrate only if toolbar is customized and the element is not found.
       if (currentset &&
           currentset.indexOf("bookmarks-menu-button-container") == -1) {
-        if (currentset.indexOf("fullscreenflex") != -1) {
-          currentset = currentset.replace(/(^|,)fullscreenflex($|,)/,
-                                          "$1bookmarks-menu-button-container,fullscreenflex$2")
-        }
-        else {
-          currentset += ",bookmarks-menu-button-container";
-        }
+        currentset += ",bookmarks-menu-button-container";
         this._setPersist(toolbarResource, currentsetResource, currentset);
       }
     }
diff --git a/browser/themes/winstripe/browser.css b/browser/themes/winstripe/browser.css
index 5f2d224f419..41c71862673 100644
--- a/browser/themes/winstripe/browser.css
+++ b/browser/themes/winstripe/browser.css
@@ -1148,7 +1148,7 @@ toolbar[mode=full] .toolbarbutton-1 > .toolbarbutton-menubutton-button {
 
 /* ::::: fullscreen window controls ::::: */
 
-#TabsToolbar > #window-controls {
+#window-controls {
   -moz-margin-start: 4px;
 }