Repeated call of customize buffer returns error

[Markus Rost]

Evaluating the form

(progn
  (defcustom test-var nil
    "No doc"
    :type '(radio string sexp))
  (customize-variable 'test-var)
  (customize-variable 'test-var))

returns an error:

widget-overlay-inactive: The widget here is not active

with *Backtrace*:

Debugger entered--Lisp error: (error "The widget here is not active")
  signal(error ("The widget here is not active"))
  error("The widget here is not active")
  widget-overlay-inactive(#<overlay from 473 to 482 in *Customize Option: Test 
Var*> nil 1 596)
  erase-buffer()
  custom-get-fresh-buffer("*Customize Option: Test Var*")
  custom-buffer-create(((test-var custom-variable)) "*Customize Option: Test 
Var*")
  customize-variable(test-var)
  (progn (defcustom test-var nil "No doc" :type (quote ...)) 
(customize-variable (quote test-var)) (customize-variable (quote test-var)))
  eval((progn (defcustom test-var nil "No doc" :type (quote ...)) 
(customize-variable (quote test-var)) (customize-variable (quote test-var))))
  eval-last-sexp-1(nil)
  eval-last-sexp(nil)
  call-interactively(eval-last-sexp)