--- a/browser/base/content/browser.css
+++ b/browser/base/content/browser.css
@@ -65,16 +65,28 @@
   min-height: 25px;
   min-width: 25px;
 }
 
 toolbar[customizable="true"] {
   -moz-binding: url("chrome://browser/content/customizableui/toolbar.xml#toolbar");
 }
 
+%ifdef MENUBAR_CAN_AUTOHIDE
+#toolbar-menubar[autohide="true"] {
+  overflow: hidden;
+}
+
+#toolbar-menubar[autohide="true"][inactive="true"]:not([customizing="true"]) {
+  min-height: 0 !important;
+  height: 0 !important;
+  -moz-appearance: none !important;
+}
+%endif
+
 %ifdef XP_MACOSX
 #toolbar-menubar {
   -moz-binding: none;
 }
 %endif
 
 panelmultiview {
   -moz-box-align: start;

--- a/toolkit/content/xul.css
+++ b/toolkit/content/xul.css
@@ -277,27 +277,16 @@ toolbar[customizing="true"][hidden="true
   display: -moz-box;
 }
 
 %ifdef XP_MACOSX
 toolbar[type="menubar"] {
   min-height: 0 !important;
   border: 0 !important;
 }
-%else
-toolbar[type="menubar"][autohide="true"] {
-  overflow: hidden;
-}
-
-toolbar[type="menubar"][autohide="true"][inactive="true"]:not([customizing="true"]) {
-  min-height: 0 !important;
-  height: 0 !important;
-  -moz-appearance: none !important;
-  border-style: none !important;
-}
 %endif
 
 toolbarspring {
   -moz-box-flex: 1000;
 }
 
 /********* menu ***********/
 

--- a/toolkit/themes/linux/global/global.css
+++ b/toolkit/themes/linux/global/global.css
@@ -14,17 +14,17 @@
 
 /* ::::: XBL bindings ::::: */
 
 menulist > menupopup {
   -moz-binding: url("chrome://global/content/bindings/popup.xml#popup-scrollbars");
 }
 
 @media (-moz-menubar-drag) {
-  toolbar[type="menubar"]:not([autohide="true"]) {
+  toolbar[type="menubar"] {
     -moz-binding: url("chrome://global/content/bindings/toolbar.xml#toolbar-drag");
   }
 }
 
 /* ::::: Variables ::::: */
 :root {
   --default-arrowpanel-background: -moz-field;
   --default-arrowpanel-color: -moz-fieldText;

--- a/toolkit/themes/osx/global/toolbar.css
+++ b/toolkit/themes/osx/global/toolbar.css
@@ -13,18 +13,16 @@ toolbox {
 toolbar {
   min-width: 1px;
   min-height: 20px;
   -moz-appearance: toolbar;
 }
 
 toolbar:-moz-lwtheme {
   -moz-appearance: none;
-  background: none;
-  border-color: transparent;
 }
 
 toolbarseparator {
   -moz-appearance: separator;
   margin: 3px 4px;
 }
 
 toolbarpaletteitem {