Add a SubMenuCategory

flask_admin/base.py

@@ -9,7 +9,7 @@ from flask_admin._compat import with_metaclass, as_unicode
 from flask_admin import helpers as h
 
 # For compatibility reasons import MenuLink
-from flask_admin.menu import MenuCategory, MenuView, MenuLink
+from flask_admin.menu import MenuCategory, MenuView, MenuLink, SubMenuCategory
 
 
 def expose(url='/', methods=('GET',)):

flask_admin/menu.py

@@ -7,7 +7,7 @@ class BaseMenu(object):
     """
     def __init__(self, name, class_name=None, icon_type=None, icon_value=None, target=None):
         self.name = name
-        self.class_name = class_name
+        self.class_name = class_name if class_name is not None else ''
         self.icon_type = icon_type
         self.icon_value = icon_value
         self.target = target
@@ -141,3 +141,10 @@ class MenuLink(BaseMenu):
 
     def get_url(self):
         return self.url or url_for(self.endpoint)
+
+
+class SubMenuCategory(MenuCategory):
+    def __init__(self, *args, **kwargs):
+        super(SubMenuCategory, self).__init__(*args, **kwargs)
+        self.class_name += ' dropdown-submenu'
+