>>682
どんなバッファでも, M-x action-lock-mode すれば OK …かなあ?

「http://foo/bar.baz」からブラウザを起動したいだけなら,
もっと標準な方法が用意されてそうに思いますけど.

>>683
(setq howm-view-title-regexp "^=\\( +\\(.*\\)\\|\\)\n")
(setq howm-view-title-regexp-pos 2)
(set-face-background 'howm-mode-title-face "yellow")

っていうのが, info のこの警告にあたってるのかわからず…

*Warning:* Do not design an element of `font-lock-keywords' to match
text which spans lines; this does not work reliably. While
`font-lock-fontify-buffer' handles multi-line patterns correctly,
updating when you edit the buffer does not, since it considers text one
line at a time.