i can not set the menu security
I see it in 1.7.9.
I can not see it in 1.8.2.
Permissions are significantly different in 1.8 series than they were in 1.7 series.
In 1.7 series you had menu and page security forms, in 1.8 there is only Page security form (but different than in 1.7).
Still similar to 1.7, if a user should have access to existing layouts, media files or displays etc then you will need to assign him permission to that specific item.