Hello,
If your user is an Administrator or if you add that User to the "main vendor" (via the global configuration), then the User will be allow to manage the entire store.
The main vendor is your store ; he has the same right as you have in the backend.
Thus I recommend you to associate the user with a specific vendor, via "HikaMarket > Vendors" and then edit the vendor to whom you want to associate the user. (Don't forget to remove that user from the main vendor)
Kind regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.