Hi,
See :
www.hikashop.com/support/documentation/i...oduct-form.html#main
Unless you have modify the interface using view override, the field "categories" accept multiple selections.
If you click on the field (and not on the "x" to delete a category), it will be able to select another category which will be added in the list.
Now some elements just accept one single category, like the "product listing" modules and menus.
There ; it will be not possible to display content of two different categories, but you can display the content of one category and his sub categories.
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.