Customizing the metamodel > What you can do with USRPROPS/SAPROPS > Layout capabilities > Grids, list boxes, and text boxes > Defining a LIST of values > Entering your own values
  
Entering your own values
If the list is provided as a dropdown list, users can select one of the values from the list, or type their own value (unless LISTONLY or LISTONLYCOMBO has been used).
See also
Defining a LIST of values