Re: w3m-form allows editing when it shouldn't

[Katsumi Yamaoka <yamaoka@xxxxxxx>]

In [emacs-w3m : No.12222] Thorsten Jolitz wrote:
> I just found out that the same problem still exists for drop-down menus,
> I can choose a different item from the drop-down items list, although
> the form is in read-only state (before the 'edit' button has been
> pressed).

> Just like with textareas, textfields and checkboxes, drop-down combos
> should not be editable in the PicoLisp Wiki before the 'edit' button is
> pressed, since the selections will be lost anyway when the page is
> submitted.

Should be fixed now.
Unfortunately w3m doesn't seem to know disabled `select' forms,
so I modified the `w3m-filter-subst-disabled-with-readonly'
filter so as to replace such ones with read-only `input' forms.
I fixed some kinds of disabled widget buttons, too.