integervalidate_Combo_item(integer item#)
** Temporarily disabled until interface for this is created!!!
** // augment left mouse down to pop up a floating panel. Default name is
** // deo_floater.
** Procedure mouse_down2 integer i1 integer i2
** integer obj
** Get Floating_panel_object to obj
** if obj eq 0 ;
** Forward Send mouse_down2 i1 i2
** else begin
** send mouse_down i1 i2 // activate
** if ( focus(desktop)=self AND ;
** Item_window(self)=i1 ) ;
** Send activate to obj
** end
** End_Procedure // mouse_down2
Validate against the combo list. report Error DFERR_BAD_ENTRY if bad!
Can be used by iValidate