Solution : https://service.sap.com/sap/support/notes/498761 (SAP Service marketplace login required)
Key words : 
input field proj-schtyp  dropdown  =  list box  deflength =  15  vislength =  17 copy, line  field   field type  schtyp  ps_sched_typeand save, lines  proj-schtyp  text  proj-schtyp, proj-schtyp left-aligned, groups/functions' tab page, create report ztfawf_projs_schtyp attached, field proj-schtyp, 'profile data' tab page, 'planning dates' box, free line drag
Related Notes : 
       
| 494256 | Project: Scheduling scenario, forecast start/finish missing |