If I want to assign a user group to a role, I have no search bar.
Steps to reproduce:
1) Go to "Control Panel" -> "Roles"
2) "Add" a "Regular Role"
3) Click Actions button -> "Assign Members"
4) Go to "User Groups" tab and in the last mentioned tab the search bar is missing.
The bar exists for the other tabs (Users, Sites, Organizations).
This Issue seems similar to