If you're experiencing Chromium mailto links opening in Thunderbird but missing the email address, it's not a Chromium problem but an xdg-utils one.
The temporary solution I found at http://www.google.com/support/forum/p/Chrome/thread?tid=1ad2c5864d13eb93&hl=en
This is not a bug in Chromium / chromium-browser. Following investigations it appears to be a bug in /usr/bin/xdg-email (part of xdg-utils) which Chromium uses to run the actual mail program.
Looks like a typo to me, altering the line starting:
TOqul=$(echo "$MAILTO" ...
TO=$(echo "$MAILTO" ...
fixes the problem.
The up-to-date xdgutils, 1.1.0, doesn't have this bug from what I can see (http://portland.freedesktop.org/wiki/
), but my pclinuxos 2011 is has installed what appears to be the 1.0.3 version.
Perhaps an xdgutils update for Pclinuxos would be a good idea - in the mean time, the workaround above does the job.