The button Cancel in the Purchase orders should be enabled only when the Purchase order has Approval Status = Confirmed. This is important because, when closing fiscal periods, the system says error if there are purchase orders canceled with Approval Status not Confirmed (but Approved, for example)
For the time being, button Cancel gets enabled only when the Purchase order is confirmed (thus Approval Status = Confirmed). Though, if the Approval status gets back to Approved, the button Cancel stays enabled and the order can be canceled even if Approval status = approved.
This represents an issue when closing fiscal periods because the system wants purchase orders to have Approval status = Confirmed even if they were Canceled.
If the purchase order could be canceled only when its Approval status is Confirmed, then such issue would not be existing.