To follow up, the message I just posted above correctly verified when it was in the text box before being submitted, but now that it's being displayed as HTML, it no longer verifies.  The white space (double spaces between sentences, etc.) is displaying correctly.  If I copy and paste it into gedit, it verifies correctly.  And if I copy and paste it into FireGPG's "Text Editor" window, it also verifies.

Bottom line: as far as I can tell, when using my version of Firefox 3/Ubuntu, verifying signed, unencrypted text from a web page using FireGPG simply doesn't work.  (The problem isn't the hyperlinks, since I have the same problem when I load a plain text file.  And verifying/decrypting encrypted messages does work.)

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Sorry to keep posting, but I continue to test this out and see what works and what doesn't.  I've concluded that, on my platform at least (Ubuntu Linux, Firefox 3), verifying a non-encrypted message using FireGPG almost never works, whether in GMail, another webmail client, or even a plain text file being viewed through Firefox 3.  Verification fails regardless of plain-text or wysiwig editing and even if the webmail client does not strip whitespace.  I haven't been able to figure out why.

Even the simplest possible test case, signing a .txt file, saving it in a text editor, opening it in Firefox, and verifying using FireGPG, does not verify, whereas the same text file verifies correctly from the command line or from within the text editor (gedit).  Whitespace is displaying correctly in Firefox.  Strangely, if I copy the same text, whether from my plain .txt file or from Gmail, from Firefox into gedit, gedit correctly verifies the exact same text that FireGPG has failed to verify, and I can save the same text and verify it from the command line using GPG.

Inexplicably, this message that I'm posting now does verify correctly.  I'm not sure why this text box is treated differently from a plain text file or an HTML file.  Could it be a problem with how Firefox 3 handles white space when rendering web pages?  Do others have this same problem in Firefox 3?

Joe Hill (0D3CE986)
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)
Comment: http://getfiregpg.org

iD8DBQFIWDBhZOor8Q086YYRAkysAJ9EALfJUbuoHbBzOMkOWN+i6wFcBQCdE7u5
3yNp3UHEf3nk9Tepl7Z7X9Q=
=NTYA
-----END PGP SIGNATURE-----

For some reason this is not what I have experienced--all the emails I have sent and received through GMail and signed and verified through firegpg have been recognized as invalid.  It doesn't matter if I use rich text, plain text, new GMail, old GMail, send to GMail or from GMail, if I sign it outside GMail and then paste it into GMail, etc.---it fails in 100% of cases.  It does work with Yahoo Mail and other web mail browsers though.

Is there some trick I should be trying to make it work?  For the moment I'm resorting to not using GMail if I want to sign something.

Correct me if I'm wrong, but it seems the moral of the story is that FireGPG can't be used from within GMail for signing, end of story?  I've tried using Gmail to send, receive, and forward within Gmail and to and from other web and non-web clients, and my conclusion is that every message that touches Gmail becomes non-verifiable.  (This is not the case with encrypted messages--for some reason they can be decrypted and verified.)

If this can't be fixed, my suggestion to the developers of FireGPG is to remove the deceptive "Sign" button from the Gmail interface.  It's simply pointless to have a button whose purpose is thwarted in 100% of cases.

Does anyone have a different experience?  I'm using Firefox 3 on Ubuntu, and I wouldn't be surprised if mileage varied for people using different platforms.

Joe