If the 'Purchase Order Detail' screen → 'Delivery' tab is displayed on a screen that has limited width, the columns in the Delivery Item List can be collapsed.
When the columns in the Delivery Items List are collapsed, the following columns are hidden:
'Sales Qty'
'Stock Qty'
To Collapse the Columns in the Delivery Item List:
Navigate to the 'Purchase Order Details' screen → 'Delivery' tab.