When entering this posting I didn't realize that the one-sentence description wasn't the whole posting, so I made it too complicated. (I've since edited it.) You should call the one-sentence field "Title" or add something to imply that the detailed entry will follow.

Sorry for the misunderstanding.

That is probably because that feed is send with content type="text/plain" instead of type="application/rss+xml"

Cor-el: Thanks for your reply. I don't think that's the problem . Here's the header tag, with "application/rss+xml" correctly entered.

<link rel="alternate" type="application/rss+xml"

href="http://bionsmalleyassoc.com/BSA_jsp/MU_test/RSS_BionWareTest.rss " title="BionWare RSS test">

I still think it's a bug in Firefox since this same page works properly in both IE9 and Safari 5.1. If there were a basic error in the page it wouldn't work anywhere.

The difference is what the server sends and that is stored in the cache headers, so Firefox doesn't know that the file was originally displayed as an XML file.

You can see that if you open Tools > Page Info > General

• http://web-sniffer.net/?url=http%3A//bionsmalleyassoc.com/BSA_jsp/MU_test/RSS_BionWareTest.rss&http=1.1&gzip=yes&type=GET&uak=0

Cor-el: So how do IE9 and Safari 5.1 get it correct? Shouldn't they have the same problem? Why is it a problem only in Firefox? But beyond that, how do I solve the problem in Firefox? Maybe I should tell it not to cache for this particular page? I'll give that a try and see if it helps.

That is a problem with the server configuration.
You need to add a rule to the .htaccess file to send that file with the correct MIME type to make that work.

• http://httpd.apache.org/docs/current/mod/mod_mime.html#AddType
• AddType application/rss+xml .rss

• https://developer.mozilla.org/en/docs/Properly_Configuring_Server_MIME_Types

Cor-el: I really appreciate your efforts, but the problem remains. I added "AddType application/rss+xml .rss" to the .htaccess file. Also, since I'm running Tomcat 5, I added mime mapping of .rss files to application/rss+xml in the /etc/web.xml that controls mime mapping. Neither change fixed the problem.

At this point I guess I just want an answer to this question: Why do both IE9 and Safari 5.1 work correctly, but Firefox does not?

If this were a server problem, I would expect all three browsers to fail. To reiterate the sequence:

1) Go to http://bionsmalleyassoc.com/BSA_jsp/MU_test 2) Select Bookmarks->Subscribe to this page 3) Note that the "Subscribe to this page" page correctly appears 4) Hit the Back button, then the Forward button. 5) Note that now the raw XML is displayed in Firefox, but in IE9 or Safari 5.1 the correct "Subscribe to this page" page appears as before.

Same server, same web page, different results in only Firefox. I can't help but conclude that the problem is in Firefox.

Thanks again for your help.

Works for me now, so you probably need to reload and bypass the cache (Ctrl+F5) to get a fresh copy of that RSS feed page.

Cor-el: Thanks for the Ctrl-F5 tip. It now works for Firefox. At the risk of seeming petulant, however, I'd still like to know why IE9 and Safari 5.1 worked correctly the first time, before I made any server changes. Also, a different copy of Firefox on a different computer (Mac) had the same problem.