Auto append signature not working

Using jQuery-1.6.2 (included with 11.10 server) roundcube does not automatically append a signature to plain text emails. If jQuery library 1.4.4 is used instead, then it works as expected. On the un-minified version from svn it is line 2828.

The failing code (from app.js) is this:

if (input_from.attr('type') == 'select-one' && $("input[name='_draft_saveid']").val() == '') {
        this.change_identity(input_from[0]);
      }

input_form.attr('type') == 'select-one' evaluates false. The javascript object does not have a 'type' attribute. It has a 0 element with a type attribute.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: roundcube-core 0.5.4+dfsg-1 [modified: usr/share/roundcube/program/include/rcube_ldap.php usr/share/roundcube/program/include/rcube_template.php usr/share/roundcube/program/js/app.js usr/share/roundcube/program/js/common.js usr/share/roundcube/skins/default/mail.css]
ProcVersionSignature: Ubuntu 3.0.0-14.23-server 3.0.9
Uname: Linux 3.0.0-14-server x86_64
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
Date: Wed Jan 18 14:28:01 2012
InstallationMedia: Ubuntu-Server 11.10 "Oneiric Ocelot" - Release amd64 (20111011)
PackageArchitecture: all
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: roundcube
UpgradeStatus: No upgrade log present (probably fresh install)
modified.conffile..etc.roundcube.apache.conf: [modified]
modified.conffile..etc.roundcube.htaccess: [modified]
mtime.conffile..etc.roundcube.apache.conf: 2011-12-16T08:17:13.261259
mtime.conffile..etc.roundcube.htaccess: 2011-12-16T08:52:42.641229