Behaviour suggestion - Editing order when being processed
One irritating thing with Prestashop is that once you set an order to preparation in progress you can not modify it. It happens quite frequently that customers make last minute changes and it is a mess if the order has already moved to Preparation in Progress state.
This thread explains the problem as well:
I just patched the database in my 1.5 installation as per the link above and it seems to work ok just changing in the ps_order_state setting delivery to 0 for the preparation in progress state. It seems however from other posters that it might work differently in 1.6 (I did not test).
I think it would be great if TB did this in a more flexible way out of the box, allowing you to edit the order until it is actually set as shipped.