isCOBOL Evolve : User Interface : Controls Reference : ENTRY-FIELD : Styles : Required
Required
When this style is set, the user will not be able to leave the field empty.
 
Example - Define an entry-field control as a mandatory field
screen section.
...
  03 screen-1-ef-4 Entry-Field
     line 40.6
     column 47.5
     size 16.2 cells 
     lines 12.3 cells 
     hint "Do not leave this field empty, please"
     id 21
     required
     3-d
     .