Customizing the metamodel : What you can do with USRPROPS/SAPROPS : Layout capabilities : Grids, list and text boxes : Defining a LIST of values : Entering your own values
  
Entering your own values
If the list is provided as a drop-down list, then the user can select one of the values from the list, or type in their own value (unless the LISTONLY or LISTONLYCOMBO command has been used - see LISTONLY or LISTONLYCOMBO command).