Last modified: 2011-04-14 15:12:45 UTC
Ever since version 1.4.3 the CategoryPageView hook has existed to modify the result of Category pages. However; this hook isn't run when the Category page is being previewed, leading to an inconsistent preview result. One extension that this effects is ShortCategory (http://www.mediawiki.org/wiki/Extension:ShortCategory).
Also as far as I know, there haven't been any hooks that fill the gap mentioned here.