From: http://alpine.x10host.com/alpine/info/fancy.html
Upstream: constitutes upstream source, delivered in non-tarball form

You can use this patch to add functionality to the thread interface offered by
Alpine. It adds commands and options that control several aspects of the way
threads are presented.


  * You can delete a thread, by pressing ^R (to remove), you can undelete it by
    pressing ^U (without this patch, you would have to collapse the thread
    before you can delete it).

  * You can select and unselect a thread, by pressing ^T. This is useful if you
    want to make aggregate operations on a thread, like saving it.

  * You can collapse or expand a particular thread by pressing [ or ]
    respectively. If you want to collapse or expand ALL threads, use the
    commands { and } respectively. These last two commands work only if you
    have selected any of the options (*)
    regular-index-with-expanded/collapsed-threads.

  * You can move to the next or previous thread by pressing ) or ( respectively.

  * You can sort threads by arrival, in order to do this press k a. There are
    other sorts for threads by Date and by Score. If you want to have threads
    permanently sorted by arrival, say, then set the variable thread-sort-key
    to be arrival. You can also start Alpine with the option -threadsort
    arrival to accomplish the same.

  * Similarly, you can sort threads by their length. In order to do this press
    k z. Small threads appear at the beginning of the listing, while long
    threads appear at the bottom. Threads of the same length are sorted
    according to the date of their first message. In particular, single message
    threads are sorted by date.

  * A new configuration option was added:
    [X] enhanced-fancy-thread-support
    if you enable this configuration option, then all of the above commands
    will act on loose threads, which are threads without parents.

  * The SIZETHREAD index token was added, which tells you the size of a thread,
    instead of the size of the individual messages in the thread.