Thread:Project:Support desk/Sidebar editing doesn't work like described in 1.20.3/reply (4)

"As an administrator of your own wiki, to edit your own MediaWiki:Sidebar, replace your wiki page's in the title bar with . (The editinterface permission needs to be enabled and is enabled for administrators by default; for information on assigning it to other groups, see Manual:User rights."

I don't get it. :/ nothing of this I can find in my mediawiki installation. where can I set the edit interface permission? i am an admin of my own wiki. i am using vector skin. is it a skin problem?