Description of problem:

Yum brought us Thunderbird 24.2 over the weekend, and now nobody here can click a link in an email and have it opened in Firefox.

I can confirm (Gnome menu / System / Preferences / More preferences / preferred applications) that Firefox is still set as the default browser. Firefox gets opened if I click an html file in Nautilus.

In Thunderbird, hovering over a link in an email still shows the URL on the status line, but clicking it has no detectable effect.

This is in RHEL 5.10.  I tried also in RHEL 6.5 and it works there.
Incompatibility with some message-passing library on 5.10? I'm just guessing. I don't know enough about whatever message library Thunderbird/Gnome/Firefox are using to launch the default browser. I did try strace -f thunderbird but I could not see anything in the trace output that was distinctive at the times I clicked on links.  If I'm given tips on how to collect more useful debugging information I'll do that and add it here.

Version-Release number of selected component (if applicable):

24.2.0 (thunderbird-24.2.0-2.el5_10)

How reproducible:

Always.

Steps to Reproduce:
1. make sure Firefox is default browser (confirm in Gnome preferences, launch on an html file in Nautilus, etc.)
2. start Thunderbird
3. click web links (the ones on the start page are fine, New Features, More Tips, etc.)


Actual results:

URL for link is displayed in status bar on mouseover, but nothing happens on click.

Expected results:

Click should launch Firefox on the link if it is not running, or open Firefox window on the link if Firefox is already running.

Additional info:

When comparing behavior on 5.10 and 6.5, I was in a gnome session on 5.10 but only ssh'd into the 6.5 box.