(form "20501" (size 55 17)
 (heading "BLOCK ATTRIBUTES")

  (label (position 3 3) (text "Block centroid"))
  (label (position 18 3) (text "Y"))
  (field "ycen" (position  19  3) (display_length 12) (max_length 20) (input disallowed))
  (label (position 30 3) (text "X"))
  (field "xcen" (position  31  3) (display_length 12) (max_length 20) (input disallowed))
  (label (position 42 3) (text "Z"))
  (field "zcen" (position  43  3) (display_length 12) (max_length 20) (input disallowed))

  (label (position 3 4) (text "Block size"))
  (label (position 18 4) (text "Y"))
  (field "ysize" (position  19  4) (display_length  8) (max_length 20) (input disallowed))
  (label (position 30 4) (text "X"))
  (field "xsize" (position  31  4) (display_length  8) (max_length 20) (input disallowed))
  (label (position 42 4) (text "Z"))
  (field "zsize" (position  43  4) (display_length  8) (max_length 20) (input disallowed))

  (scroll_block "main" (position  3  6) (size 48 10)
     (extra  0  1)
     (repeat interactive (grow  0  1) (instances  1 (min  1) (max 200)))
    (top
      (label (position  1  0) (text "Attribute"))
      (label (position 24  0) (text "Value"))
    )
    (main
      (field "attribute" (position  1  0) (display_length  20)
        (max_length "BM_MAX_ATT_NAME_LEN"))
      (field "value" (position 24  0) (display_length  20) (input allowed)
        (max_length 64) (null allowed))
    )
  )
 (default_buttons)
)