Solution : https://service.sap.com/sap/support/notes/325777 (SAP Service marketplace login required)
Key words :
message 'save entered document, additional key words me51n, icon 'display header text', header texts tab strip, field 'texts exist', long text editor, item texts exist, change header, item texts, transaction me51n
Related Notes :
| 353584 | ME51N, ME52N: problems with texts in PReq |
| 352071 | ME51N: text not copied during copy process |
| 338951 | ME51N Indicator 'Texts exist' SAPscript editor |
| 330397 | ME51N: Changes header text |