Solution : https://service.sap.com/sap/support/notes/594474 (SAP Service marketplace login required)
Key words :
select field txtgr - click, 'text determination' customizing, text determination procedure, entry 'ttxg tdobject', table - click 'change', foreign key dependency, 'foreign key' pushbutton, sales activity type, transaction se11 - enter, 'foreign key field'
Related Notes :
| 574841 | There are various errors/ms in transaction VOTXN. |