Controlling Gadgets :

  These event commands can be used to control the behaviour
  of gadgets and guis.

  SetGad        GuiFile GadIDs ON|OFF|SHOW|HIDE  (Arexx capable)
  Update        GuiFile GadID Value   (Arexx capable)
  ChangeArg     GuiFile GadID ArgNumber NewValue
  ChangeGad     GuiFile GadID L T W H Title
  ReDraw        GuiFile
  PartReDraw    GuiFile L T W H
  GadReDraw     GuiFile LeftGad Top Right Bottom Offset
  ChangeIcon    GuiFile GadID L T NewIconName
  SetAttr       GuiFile/GadID AttributeName Value
  SetGadValues  GuiFile