Back-end change of order regarding Shipping and Payment method

-- HikaShop version -- : 3.0.1
-- Joomla version -- : 3.7.2
-- PHP version -- : 5.6.30
-- Browser(s) name and version -- : chrome 58.0.3029.110 (64-bit)

When editing the order by the administrator in the back-end in the 'Additional information' frame, i do get a pop-up where i can choose another Payment or Shipping method. When i do so and change (or just for the first time fill in a method) price and tax are not pre-filled by the system but stay empty (so i have to look that up and calculate the tax myself).

This is probably not the way it is supposed to work.

Hi,

It is "normally" like that.
The shipping and payment plugins and the taxes system is supposed to calculate the taxes based on a cart with the address of the current user.
Having the system calculate taxes based on an already created order with the address of the order is not something that can easily be plugged in there. That's why the tax is not prefilled.
It's something we would like to improve in the future but it is not a priority since it's not something a merchant usually need and in such rare case, he can calculate it manually.