[Plugin: User Access Manager] Access restriction to posts does not work

The plugin does not seem to work as advertised – I create a group and put a user into this group with role editor and create a new post that is assigned to this group – the user still has access to all posts and can edit other posts without any restriction. This happens even if “do not show posts” is selected in settings page of plugin.

http://wordpress.org/extend/plugins/user-access-manager/