Hi,
Yes ; in Joomla 3 the dropdown are "rewritten" but the chosen library.
It provides a better looking way for a multi-select dropdown. But the way that the browser will display it natively is what you see in the J2.5 backend.
Thanks to the namebox system that I added in HikaShop ; we might improve that display for J2.5 by using a namebox instead of a dropdown.
But it will require some time and some tests to be sure it is working properly (and I won't be able to perform that task for the moment, I already have big development on the move)
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.