recalculate taxes, if I change the order in the backend

[fivemarcus]

Hi,

if i edit an order in the backend, changing prices and quantities, only the order total is calculated, the taxes remain the same.

So if i have an item that cost 1€ and is taxed at 10%, and i bought one of that, i will pay 1,10€

If in the backend i edit the quantity, and i set 5 item, the price become 5,10€, and not 5,5€ as expected,
the taxes remain at  0,10€ even if i edited the quantity of the product.

How can i solve?

 

thank you