Solution : https://service.sap.com/sap/support/notes/512481 (SAP Service marketplace login required)
Key words :
menu option 'edit' -> 'check availability', 'delivery group correlation apo' button, 'check item availability' button, delivery group correlation reason, manual delivery group, source code corrections, schedule line overviews, key combination <ctrl> +, schedule line overview, atp-relevant data
Related Notes :
| 440179 | Global ATP in APO (Releases 3.0, 3.1) - Composite SAP note |