[Mediawiki-l] Extension help: why is text appearing twice?

[Daniel Barrett]

This fixed the problem (making sure all hook functions returned true).
Thank you Ryan, Jim, and Rob for your help!

On a related topic, while developing this extension (to display
additional information on a wiki page), I saw some really weird caching
behavior.  If someone edited a page and saved it, the additional text
would sometimes disappear from the page; however, if you hit the
"permanent link" (?oldid=nnnn) the text was present.  Logging out &
logging in as a different user also cleared up the problem, but if you
logged back in as the first user, the problems returned.  Clearing
browser caches had no effect.

DanB