Hi,
1. Yes it's an anchor so you'll see directly the zone that you were editing (when using the auto-submit).
2. You have an option in HikaShop to force the menu on the checkout, it allows you to force the menu for the checkout.
3. Each user will have a different session, they won't have any issue.
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.