■ You have double-clicked an object in the Form Designer.
  Unlike the Windows version, Visual Basic for MS-DOS does
  not allow you to add code by double-clicking a form or
  control.
 
■ Possible solutions:
 
  • If you started the Form Designer from the MS-DOS command
    line:
    ♦ Save the current project.
    ♦ Press Alt+F4 to exit the Form Designer.
    ♦ Start Visual Basic for MS-DOS.
    ♦ Open the project.
    ♦ Press F12 to open the event procedures dialog and add
      code.
 
■ If you need additional help, move the cursor to a keyword
  and press F1 to open the Help window.