sorry
it is named current activity,
I am sure all forums have default usergroups permissions !
--------------- Added [DATE]1252818864[/DATE] at [TIME]1252818864[/TIME] ---------------
Problem solved
it was because of the mod :
The Image Resizer. Powered with Lytebox / Highslide / Lightview / and many more!
bug reported
--------------- Added [DATE]1252819216[/DATE] at [TIME]1252819216[/TIME] ---------------
you should disable then re-enable the mod !
problem solved