I have relative links in a menu page of the form:

<li><a href="info.htm#part1">See Part 1 of the problem</a></li>

In the target page, the anchor is made as follows:

<h1><a name="part1">Part 1 of the Problem</a></h1>

Now, after upgrading to Firefox 4, I am getting a 405 error:

URL /Part1.html not found.

IE works OK on the same links.

That error message does not even make any sense. Part1 is not the URL for the page.

I found the trouble. Firefox 4 somehow dug up a week-old version of the menu page from the cache. The urls of those pages were different in the old version. Yet, FF 3.6 had displayed the new version correctly for a week.

I found the trouble by viewing the source. It didn't match my new code.

Refreshing the page fixed it. I didn't think of it, because the FF 3.6 had been displaying the new page for a week.

Now, how do we keep software companies from changing your settings when they upgrade your software? I found automatic checking for new versions of web pages disabled.