Solution : https://service.sap.com/sap/support/notes/1120626 (SAP Service marketplace login required)
Key words :
dropdown vanishes inside table, web dynpro foundation, entrylist taking care, terms dynamic entrylist, table/gridview, dynamic entrylist, composition environment, specific column, selected values, previously shown
Related Notes :
| 1021219 | Central Note: Visual Composer for NetWeaver 7.1 CE |