Insight freeze

Remove reference to admin security context.
Refresh the tree when the group permissions have been modified.
The user switch and group permissions could be the source of the freeze. The group permissions will have to be reviewed in depth but this is outside the scope of this PR.

To test:
 * log in as a user in multiple groups. The user needs to be owner of a group.
 * Modify the permission of the group. 
 * Check that the tree is refreshed.