Solution : https://service.sap.com/sap/support/notes/69452 (SAP Service marketplace login required)
Key words : 
type length checktable short text plnty          plnty      char      1           task list type plnnr          plnnr      char      8            group key sttag          sttag_com  dats      8            mult, task list group field, additional key words duplicated component allocation, ~/ftp/general/r3server/abap/score, prerequisites multiple component allocations, recent component allocation, reference operation set, source code specific, lowest operation number, activate structure rc27re_com
Related Notes : 
       
| 126846 | |
| 101281 | CA01: Upgrade problem for component allocation | 
| 98422 | Deleting links | 
| 89729 | Missing components after upgrade from 2.2 to 3.x |