PRO changefield, base, newfieldname, BOXZOOM = boxzoom
;
;
  compile_opt idl2, strictarrsubs
;
  widget_control, base, get_uvalue = top_uvalue
;
; Change exextra :
  exextra = definedefaultextra(newfieldname)
  specifieid = widget_info(base, find_by_uname = 'specifie')
  widget_control, specifieid, set_value = exextra
; Change the variable -> Do we need to change the vertical axis
; according to the tye of points (T or W)?
  dthlv1id = widget_info(base, find_by_uname = 'dthlv1')
  widget_control, dthlv1id, get_uvalue = dthlv1_uval
  oldzgridt = dthlv1_uval.grid_t
; get the type of point
  currentfile = extractatt(top_uvalue, 'currentfile')
  listgrid = (*(extractatt(top_uvalue, 'fileparameters'))[currentfile]).listgrid
  listvar = (*(extractatt(top_uvalue, 'fileparameters'))[currentfile]).listvar
;   for i = 0,  n_elements(listvar)-1 do print,  listvar[i], '/', listgrid[i]
  indexvar = where(listvar EQ newfieldname)
  indexvar = 0 > indexvar[0]
  zgridt = strupcase(listgrid[indexvar]) NE 'W'
; if we change the type of point
  if zgridt NE oldzgridt then BEGIN
; update dthlv1_uval.grid_t
    dthlv1_uval.grid_t = zgridt
    widget_control, dthlv1id, set_uvalue = dthlv1_uval
; update cw_domain
    if NOT keyword_set(boxzoom) THEN $
       widget_control, widget_info(base, find_by_uname = 'domain'), get_value = boxzoom
    widget_control, widget_info(base, find_by_uname = 'domain'), set_value = boxzoom
  endif
;
  return
end