Solution : https://service.sap.com/sap/support/notes/713505 (SAP Service marketplace login required)
Key words :
01 create 02 change 03 display 20 enter actual dates 21 change dates 22 display dates, structure psmlstd_context change data type psmlstd_context, component component typepssv_active char1 activate, milestone detail screen reason, attached program correction, detail screen, milestone overview, program error, wbs element, terms cnex0002
Related Notes :
| 685010 | Scheduled date of milestone is not updated |
| 314984 | Milestones in Project Builder |