Too many groups break "Add new user" form

[alecghica]

How to reproduce

1. login as a Manager
2. create many user groups
3. check "Many groups?" under @@usergroup-controlpanel
4. click "Add new user" under @@usergroup-userprefs

The issue

The above steps will make the "Add new user" form to take a huge amount of time to load. This become worst if you use/have many LDAP groups.

Expected behavior

When "Many groups?" is checked under @@usergroup-controlpanel it should not list anymore the groups to the "Add new user" form.

Suggested solution

Under plone.app.user.browser.register.py module hide the groups listing under from the "Add new user" form based on portal_properties.site_properties.many_groups value.

[avoinea]

Fixed.