'Search all User categories for items named item_name with category
item_category and delete them. The caller must arrange to redisplay the
tree as appropriate.'

def delete_item_from_all_user_categories(self, item_name, item_category):

    user_cats = self.db.prefs.get(u'user_categories', {})
    for cat in user_cats.keys():
        self.delete_item_from_user_category(cat, item_name, item_category, user_categories=user_cats)
    self.db.new_api.set_pref(u'user_categories', user_cats)
