[BUG] Two problems with defcustom of org-structure-template-alist

[Nick Dokos <ndokos@gmail.com>]

There seem to be two problem in the defcustom of
org-structure-template-alist. It looks like this:

--8<---------------cut here---------------start------------->8---
  :type '(repeat
	  (string :tag "Key")
	  (string :tag "Template")
	  (string :tag "Muse Template")))
--8<---------------cut here---------------end--------------->8---

and afaict, this is not well-formed, so when I try to customize it,
I get a (mismatch). I believe it should look like this:

--8<---------------cut here---------------start------------->8---
  :type '(repeat
          (list
 	   (string :tag "Key")
	   (string :tag "Template")
	   (string :tag "Muse Template"))))
--8<---------------cut here---------------end--------------->8---

That's the first problem, but even after doing this, I still get a
(mismatch).

I think the (second) problem now is that the Muse Template is not
optional as far as defcustom is concerned, but there are entries in the
list above with only two elements. If I add a third element (an empty
string) to those entries missing it, I can customize to my heart's
content.

The question is: is the Muse Template optional? If so, how does one
tell defcustom that? I did a cursory reading of the customization
chapter in the elisp manual but my brain refuses to cooperate.

GNU Emacs 24.3.50.2 (x86_64-unknown-linux-gnu, GTK+ Version 2.24.10) of
2013-06-17 on pierrot
Org-mode version 8.0.3 (release_8.0.3-358-gb0174f @
/home/nick/elisp/org-mode/lisp/)

Thanks!
-- 
Nick