Hi,

Thank you for contributing a good feature.  I tried it today and
realized it is really useful.  Though I have no plan for the moment,
people might want a browser function for many sticky articles. :)

Please let me write about a few problems in `gnus-sticky-article'.

1. (gnus-configure-windows 'article) makes an empty article
   buffer and leads creating of an empty sticky article if there
   is no article buffer initially, but is not necessary because
   `gnus-summary-select-article' runs it by way of
   `gnus-summary-display-article' and `gnus-article-prepare'
   after preparing an article.

2. It seems to be useless that this command always makes a new
   sticky article buffer.  I mean, performing of the `A S'
   command repeatedly on an article creates "*Sticky Article*",
   "*Sticky Article*<2>", "*Sticky Article*<3>"...

3. The value of the `gnus-article-buffer' variable in the summary
   buffer is not updated when I select another (normal) article.
   Because of this, a non-ASCII article or a QP-encoded article
   is not decoded when I type `P' or `N' in the summary buffer.

4. I wish you to leave the value of the `indent-tabs-mode'
   variable the default if there is no good reason.  Now some
   lines are indented with tabs but others aren't.

I tried improving these problems.  Here are a replacement of the
`gnus-sticky-article' function and a patch for gnus-sum.el: