The reasone that it doesn't count children up fron is simple: it would require a
lot of database queries, the reult of which would rarely be used. I'm not aware
of any way to do this nice and fast.

Why safari displays "undefined" there I don't know... and I don't have safar to
test it. I'll ask around.

This appears to be a safari bug - "undefined undefind" refers to the status and
statusText fields of the XMLHttpRequest object, which *must* always be
available, as per specification.

I have found reports about Safari sometimes not setting these fields, but not
about this specific case - it seems this is triggered when the response from the
server is empty. I'm currently trying to find a workaround - I can't think of a
good way right now, though.

Does this happen for *all* "terminal" subcategories for you? Always? Does it
sometimes happen in other cases as well? Especially, check this: if you expand a
category node, then reload the page, then expand the same node again - does that
trigger an error?

For reference:
http://www.bitterpill.org/bp/2005-06/safari-xmlhttprequest-undefine.html
describes a problem related to If-Modified-Since caching, with the same symptoms.

fastfission wrote:

I've seen it in all terminal subcategories, even if I do many of them at the same time. I tried the reloading-and-clicking
and it does the same thing. Even if I open a node and then close it and open it again. It seems to strike-out in Safari each
time.

I can see why not to look for children ahead of time; and I imagine keeping a static childcount for any individual category
would take some substantial re-working of the way things are currently done.

Relevant Webkit bug: http://bugzilla.opendarwin.org/show_bug.cgi?id=10638

Scrap the above, now filed as a separate issue:
http://bugzilla.opendarwin.org/show_bug.cgi?id=10716

I have committed a workaround in r16377. I hope that fixes the problem, I don't
have Safari to test.

The workaround is active on wikipedia now, please check if the problem has gone
away. You can reopen the bug if it's not OK.