Solution : https://service.sap.com/sap/support/notes/216488 (SAP Service marketplace login required)
Key words : 
additional key words sapscript, transfer protected text lines, locked text lines, sapscript pc editor, front end patch, subsequent text appears, text consists exclusively, paragraph left-aligned, editor combo box, standard paragraph format
Related Notes : 
       
| 396958 | SAPscript: Inserting Clipboard deletes locked text lines | 
| 363243 | SAPscript: Collective note for template lines | 
| 337373 | SAPscript: copy locked texts to clipboard | 
| 305856 | SAPscript: Locked text lines deleted | 
| 302655 | SAPscript: Clipboard overwrites locked texts | 
| 302319 | SAPscript: Locked text lines can be edited | 
| 96885 | Downloading front end patches |