menu with category_icon_classes bug

[fordguo]

`
category_icon_classes = {"System": "glyphicon glyphicon-wrench"}

admin = Admin(
template_mode="bootstrap3",
category_icon_classes=category_icon_classes)`

The related code is:

flask-admin/flask_admin/templates/bootstrap3/admin/layout.html

Line 27 in 280c76b

<li class="dropdown{% if class_name %} {{class_name}}{% endif %}">

[fwiersENO]

Work-around I use for 1.5.3:

from flask_babelex import lazy_gettext
from flask_admin.consts import ICON_TYPE_GLYPH

def add_views():
	mycat = lazy_gettext('My Category')
	admin.add_view(MyAdminView(... , category=mycat, ...)
	...
	# ONLY set icon for category AFTER adding a menu-item to the category.
	for item in admin.menu():
		if item.is_category():
			if item.name == mycat:
				item.icon_type = ICON_TYPE_GLYPH
				item.icon_value = "glyphicon-wrench"
				break