From a fresh ezPlatform 1.8 installation with the Legacy Bridge, here are the steps to reproduce the problem :

STEP #1: connect to the Legacy Administration Tool
STEP #2: in the user accounts menu, change the section linked to user group "Guest accounts" from "users" to "standard"
STEP #3: click on the user group "Guest accounts"

Expected behavior: I can see the detail information of the group, especially the roles and policies. The left pan still displays the list of user groups and the menu "User accounts" is selected.

Actual behavior: I can't see the roles and policies in the detail information of the user group. The left pan displays the content structure and the menu "Content Structure" is selected.
In fact since the section of the user group (or user) is changed (different from "users") the context "user accounts" is lost.