diff --git a/toolkit/themes/gnomestripe/global/menu.css b/toolkit/themes/gnomestripe/global/menu.css
index bcd5a1567cd3..763c36ed4e94 100644
--- a/toolkit/themes/gnomestripe/global/menu.css
+++ b/toolkit/themes/gnomestripe/global/menu.css
@@ -202,14 +202,14 @@ menuitem[type="radio"] {
 /* ::::: menuseparator ::::: */
 
 menuseparator {
-  margin: 2px 3px;
+  -moz-appearance: menuseparator !important;
+  margin: 2px 0;
   border-top: 1px solid ThreeDShadow;
   border-bottom: 1px solid ThreeDHighlight;
 }
 
 menulist > menupopup > menuseparator,
 .menulist-menupopup > menuseparator {
-  margin: 2px 0;
   border-top: 1px solid #000000;
   border-bottom: none;
 }
diff --git a/widget/src/gtk2/gtk2drawing.c b/widget/src/gtk2/gtk2drawing.c
index 3e34daec458d..c2debcaeea87 100644
--- a/widget/src/gtk2/gtk2drawing.c
+++ b/widget/src/gtk2/gtk2drawing.c
@@ -85,6 +85,7 @@ static GtkWidget* gTreeHeaderCellWidget;
 static GtkWidget* gTreeHeaderSortArrowWidget;
 static GtkWidget* gExpanderWidget;
 static GtkWidget* gToolbarSeparatorWidget;
+static GtkWidget* gMenuSeparatorWidget;
 
 static GtkShadowType gMenuBarShadowType;
 static GtkShadowType gToolbarShadowType;
@@ -375,6 +376,19 @@ ensure_menu_item_widget()
     return MOZ_GTK_SUCCESS;
 }
 
+static gint
+ensure_menu_separator_widget()
+{
+    if (!gMenuSeparatorWidget) {
+        ensure_menu_popup_widget();
+        gMenuSeparatorWidget = gtk_separator_menu_item_new();
+        gtk_menu_shell_append(GTK_MENU_SHELL(gMenuPopupWidget),
+                              gMenuSeparatorWidget);
+        gtk_widget_realize(gMenuSeparatorWidget);
+    }
+    return MOZ_GTK_SUCCESS;
+}
+
 static gint
 ensure_check_menu_item_widget()
 {
@@ -1641,6 +1655,55 @@ moz_gtk_menu_popup_paint(GdkDrawable* drawable, GdkRectangle* rect,
     return MOZ_GTK_SUCCESS;
 }
 
+static gint
+moz_gtk_menu_separator_paint(GdkDrawable* drawable, GdkRectangle* rect,
+                             GdkRectangle* cliprect)
+{
+    GtkStyle* style;
+    gboolean wide_separators;
+    gint separator_height;
+    guint horizontal_padding;
+    gint paint_height;
+
+    ensure_menu_separator_widget();
+
+    style = gMenuSeparatorWidget->style;
+
+    gtk_widget_style_get(gMenuSeparatorWidget,
+                         "wide-separators",    &wide_separators,
+                         "separator-height",   &separator_height,
+                         "horizontal-padding", &horizontal_padding,
+                         NULL);
+
+    TSOffsetStyleGCs(style, rect->x, rect->y);
+
+    if (wide_separators) {
+        if (separator_height > rect->height)
+            separator_height = rect->height;
+
+        gtk_paint_box(style, drawable,
+                      GTK_STATE_NORMAL, GTK_SHADOW_ETCHED_OUT,
+                      cliprect, gMenuSeparatorWidget, "hseparator",
+                      rect->x + horizontal_padding + style->xthickness,
+                      rect->y + (rect->height - separator_height - style->ythickness) / 2,
+                      rect->width - 2 * (horizontal_padding + style->xthickness),
+                      separator_height);
+    } else {
+        paint_height = style->ythickness;
+        if (paint_height > rect->height)
+            paint_height = rect->height;
+
+        gtk_paint_hline(style, drawable,
+                        GTK_STATE_NORMAL, cliprect, gMenuSeparatorWidget,
+                        "menuitem",
+                        rect->x + horizontal_padding + style->xthickness,
+                        rect->x + rect->width - horizontal_padding - style->xthickness - 1,
+                        rect->y + (rect->height - style->ythickness) / 2);
+    }
+
+    return MOZ_GTK_SUCCESS;
+}
+
 static gint
 moz_gtk_menu_item_paint(GdkDrawable* drawable, GdkRectangle* rect,
                         GdkRectangle* cliprect, GtkWidgetState* state,
@@ -1990,6 +2053,7 @@ moz_gtk_get_widget_border(GtkThemeWidgetType widget, gint* left, gint* top,
     case MOZ_GTK_TAB:
     case MOZ_GTK_EXPANDER:
     case MOZ_GTK_TOOLBAR_SEPARATOR:
+    case MOZ_GTK_MENUSEPARATOR:
     /* These widgets have no borders.*/
     case MOZ_GTK_TOOLTIP:
     case MOZ_GTK_WINDOW:
@@ -2062,6 +2126,27 @@ moz_gtk_get_expander_size(gint* size)
     return MOZ_GTK_SUCCESS;
 }
 
+gint
+moz_gtk_get_menu_separator_height(gint *size)
+{
+    gboolean wide_separators;
+    gint     separator_height;
+
+    ensure_menu_separator_widget();
+
+    gtk_widget_style_get(gMenuSeparatorWidget,
+                          "wide-separators",  &wide_separators,
+                          "separator-height", &separator_height,
+                          NULL);
+
+    if (wide_separators)
+        *size = separator_height + gMenuSeparatorWidget->style->ythickness;
+    else
+        *size = gMenuSeparatorWidget->style->ythickness * 2;
+
+    return MOZ_GTK_SUCCESS;
+}
+
 gint
 moz_gtk_get_scalethumb_metrics(GtkOrientation orient, gint* thumb_length, gint* thumb_height)
 {
@@ -2213,6 +2298,9 @@ moz_gtk_widget_paint(GtkThemeWidgetType widget, GdkDrawable* drawable,
     case MOZ_GTK_MENUPOPUP:
         return moz_gtk_menu_popup_paint(drawable, rect, cliprect);
         break;
+    case MOZ_GTK_MENUSEPARATOR:
+        return moz_gtk_menu_separator_paint(drawable, rect, cliprect);
+        break;
     case MOZ_GTK_MENUITEM:
         return moz_gtk_menu_item_paint(drawable, rect, cliprect, state, flags);
         break;
@@ -2281,6 +2369,7 @@ moz_gtk_shutdown()
     gTreeHeaderSortArrowWidget = NULL;
     gExpanderWidget = NULL;
     gToolbarSeparatorWidget = NULL;
+    gMenuSeparatorWidget = NULL;
 
     is_initialized = FALSE;
 
diff --git a/widget/src/gtk2/gtkdrawing.h b/widget/src/gtk2/gtkdrawing.h
index fd8e4e3fffcf..1ca7f7c065f6 100644
--- a/widget/src/gtk2/gtkdrawing.h
+++ b/widget/src/gtk2/gtkdrawing.h
@@ -182,6 +182,7 @@ typedef enum {
   MOZ_GTK_MENUITEM,
   MOZ_GTK_CHECKMENUITEM,
   MOZ_GTK_RADIOMENUITEM,
+  MOZ_GTK_MENUSEPARATOR,
   /* Paints the background of a window, dialog or page. */
   MOZ_GTK_WINDOW
 } GtkThemeWidgetType;
@@ -322,6 +323,14 @@ gint moz_gtk_get_toolbar_separator_width(gint* size);
  */
 gint moz_gtk_get_expander_size(gint* size);
 
+/**
+ * Get the desired height of a menu separator
+ * size:    [OUT] the desired height
+ *
+ * returns: MOZ_GTK_SUCCESS if there was no error, an error code otherwise
+ */
+gint moz_gtk_get_menu_separator_height(gint* size);
+
 /**
  * Retrieve an actual GTK scrollbar widget for style analysis. It will not
  * be modified.
diff --git a/widget/src/gtk2/nsNativeThemeGTK.cpp b/widget/src/gtk2/nsNativeThemeGTK.cpp
index f00f293f173a..1442456ca062 100644
--- a/widget/src/gtk2/nsNativeThemeGTK.cpp
+++ b/widget/src/gtk2/nsNativeThemeGTK.cpp
@@ -275,6 +275,7 @@ nsNativeThemeGTK::GetGtkWidgetAndState(PRUint8 aWidgetType, nsIFrame* aFrame,
         if (aWidgetType == NS_THEME_MENUITEM ||
             aWidgetType == NS_THEME_CHECKMENUITEM ||
             aWidgetType == NS_THEME_RADIOMENUITEM ||
+            aWidgetType == NS_THEME_MENUSEPARATOR ||
             aWidgetType == NS_THEME_MENUARROW) {
           PRBool isTopLevel = PR_FALSE;
           nsIMenuFrame *menuFrame;
@@ -503,6 +504,9 @@ nsNativeThemeGTK::GetGtkWidgetAndState(PRUint8 aWidgetType, nsIFrame* aFrame,
   case NS_THEME_MENUITEM:
     aGtkWidgetType = MOZ_GTK_MENUITEM;
     break;
+  case NS_THEME_MENUSEPARATOR:
+    aGtkWidgetType = MOZ_GTK_MENUSEPARATOR;
+    break;
   case NS_THEME_MENUARROW:
     aGtkWidgetType = MOZ_GTK_MENUARROW;
     break;
@@ -904,6 +908,16 @@ nsNativeThemeGTK::GetMinimumWidgetSize(nsIRenderingContext* aContext,
       *aIsOverridable = PR_FALSE;
     }
     break;
+  case NS_THEME_MENUSEPARATOR:
+    {
+      gint separator_height;
+
+      moz_gtk_get_menu_separator_height(&separator_height);
+      aResult->height = separator_height;
+    
+      *aIsOverridable = PR_FALSE;
+    }
+    break;
   case NS_THEME_CHECKBOX:
   case NS_THEME_CHECKBOX_SMALL:
   case NS_THEME_RADIO:
@@ -991,6 +1005,7 @@ nsNativeThemeGTK::WidgetStateChanged(nsIFrame* aFrame, PRUint8 aWidgetType,
       aWidgetType == NS_THEME_MENUPOPUP ||
       aWidgetType == NS_THEME_TOOLTIP ||
       aWidgetType == NS_THEME_TREEVIEW_HEADER_SORTARROW ||
+      aWidgetType == NS_THEME_MENUSEPARATOR ||
       aWidgetType == NS_THEME_WINDOW ||
       aWidgetType == NS_THEME_DIALOG) {
     *aShouldRepaint = PR_FALSE;
@@ -1114,6 +1129,7 @@ nsNativeThemeGTK::ThemeSupportsWidget(nsPresContext* aPresContext,
   case NS_THEME_MENUPOPUP:
   case NS_THEME_MENUITEM:
   case NS_THEME_MENUARROW:
+  case NS_THEME_MENUSEPARATOR:
   case NS_THEME_CHECKMENUITEM:
   case NS_THEME_RADIOMENUITEM:
   case NS_THEME_WINDOW: