I realized that I see the restore button only with my admin account in my dokuwiki.
I gave maximum rigths to others users (Create / Upload / Delete) in Access Control List Management but only the admin can see the restore button when consulting an old revision of a page.
Did I miss something ?
Thank you for your help.
Here what I see as admin. The others users see all the buttons excepted the restore one :
I used the last version of dokuwiki (2018-04-22b "Greebo") with these plugins :