Dear experts
I found an unexpected error with Sales order.
I created a sales order with a zero percent sales tax and I forgot to untick Prices include sales tax check box.
After I posted this sales order, I found that its invoice amount is *-1 from net amount in sales order line.
I even can't make credit note because its credit note amount is also -480 and this customer balance has been doubled.
I tested several times and found that zero percent sales tax and tick mark in Prices include sales tax make this issue and I can't understand this logic.
Can anyone explain me why this happens?
And I'm worrying that users can have same mistakes afterward, so do you have any better setup for preventing this error?
