SETGAD   GuiFile  GadID/range   ON|OFF|SHOW|HIDE

 This command will set the specified gadget ON or OFF or make it
 appear (SHOW) or disappear (HIDE)

  GuiFile  - The name of the GUI file the gadgets reside in.

 GadID   - The  ID number  you have given to 
           the gadget, *or* a range of gadgets denoted as 
           First/LastGadget

 Example :

 SetGad MyGui.gc   10 OFF   - will set Gad No.10 off
 SetGad MyGui.gc 5/15 HIDE  - will hide gadgets Nos. 5 to 15 inclusive

 The SHOW and HIDE keywords will have no immediate visible effect
 unless and until the   ReDraw  command is used.

 ------->>>> A note about ListViews:

 LVs get updated if OFF, but not updated if HIDEn (even if visible)

 It is *much* faster to HIDE an lv and act on it (with commands
 like lvadd, lvput etc) and then SHOW it again, than to have the LV
 updated continuously while actions are going on. When you show it 
 again, you must "nudge" it into redrawing itself - with LVMULTI SHOW
 or LVMOVE 0