Unable to select Thunderbird as preferred email app

[Ric Flomag]

Binary package hint: thunderbird

In Natty (updated as of 03/15/2011), gnome-default-applications-properties does not allow to select Thunderbird as the default email app, though it is installed. See attached screenshot.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: thunderbird 3.1.9+nobinonly-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-6.34-generic 2.6.38-rc7
Uname: Linux 2.6.38-6-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Tue Mar 15 16:34:11 2011
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha amd64 (20110223)
ProcEnviron:
 LANGUAGE=es_DO:es:en_GB:en
 LANG=es_DO.UTF-8
 SHELL=/bin/bash
SourcePackage: thunderbird
UpgradeStatus: No upgrade log present (probably fresh install)