Hi!
Currently, the class_group override condition isn't working for the content/edit.tpl template although is documented here http://ez.no/doc/ez_publish/technical_manual/4_x/reference/template_override_conditions/content_edit_tpl. The problem is that the class_group key is missed from eZTemplateDesignResource::setKeys method.

Attached, I give them a simple patch.
I hope this patch will be included in the next eZNetwork's Service Pack.