Here are the commands for use in the GUMPMENU section of the UOX3.BSC; be careful though, as the server does NOT parse those, but does directly send them to the client, so it might cause you to crash: (Comments on the items I marked as "unknown" would be greatly appreciated)

- noclose
  Sets the gump so you can only close it by clicking one of the buttons on it.
- nomove
  Disallows moving the gump around.
- page x
  The objects following this command will be put on a certain page of the menu. A special case is page 0; those items are visible independant of the current page.
- text x y hue line
  Puts a line of text at the given coordinates. The line has to be present in the corresponding GUMPTEXT entry. (For GUMPMENU 1, put all text in GUMPTEXT 1 and so on)
- resizepic x y gumpstart xsize ysize
  This is for the "background" of menus. Gumpstart should point to the beginning of a certain set of 9 gumps displaying the edges and fill of the background. (For example: 5100 is the standard grey background, 5120 is a bit darker, 5170 is a scroll)
- button x y gump pressedgump close action exitcode
  This is a button that you can click. If close is >0, the button is closing the menu if clicked. If action is 1, it flips one page backward; if it is 2 it is going forward. Exitcode has no meaning for THIS version of UOX.
- radio x y gump selectedgump default resultcode
  This is a radiobutton. If default is 1 then this is the default selection for the menu.
- checkbox x y gump selectedgump default resultcode
  Same as radio, but many of those can be switched on at a time.
- gumppic x y gump
  This is placing a decorative gump with no functionality.
- tilepic x y tile
  Same as gumppic, but this one is placing an item tile.
- nodispose
  UNKNOWN (Didnt see any change)
- textentry
  UNKNOWN (This crashed my client; can anyone get it to work?)
- group
  UNKNOWN (Never noticed anything with this command)