Hi,
I guess you should be logged with a super admin user in the Joomla backend.
The popup is called by HikaShop but it's a Joomla feature which is called and, if your account does not have the right to edit the access levels, the button would not be displayed.
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.