(form "00688" (size 50 9)
  (help "00688_TIP_0")  
  (heading "ENTER DATA/MESH OPTIONS")

  (label (position  2  3) (text "Layer containing data"))
  (field "layer_name" (position 25  3) (display_length 15) (input allowed)
    (null disallowed) (max_length "APP_MAX_LAYER_NAME_LENGTH")
    (help "00688_TIP_1")
  )
  (menu (position 35 5) (size 9 1)
    (item (text "Calculate grid mesh size")
          (function "default_step_lengths")
    )
  )
  (label (position  2  5) (text "Y grid step size"))

  (field "y_step" (position 25  5) (display_length 12) (input allowed)
    (format real_8) 
    (translate lower)  (max_length 32)
    (help "00688_TIP_2")
  )

  (label (position  2  6) (text "X grid step size"))

  (field "x_step" (position 25  6) (display_length 12) (input allowed)
    (format real_8) 
    (translate lower) (max_length 32)
    (help "00688_TIP_3")
  )
 (default_buttons)
)