Characters in terminal (;~5) when Ctrl+PgUp/Dn when no other tabs present

When you have a terminal window open with a single tab, the keys for switching tabs (Ctrl+PgUp/PgDn) produce characters in the terminal; specifically Ctrl+PgDn produces ";5~" and Ctrl+PgUp produces "5~".

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: gnome-terminal 3.0.1-0ubuntu3
ProcVersionSignature: Ubuntu 3.0.0-13.22-generic-pae 3.0.6
Uname: Linux 3.0.0-13-generic-pae i686
ApportVersion: 1.23-0ubuntu3
Architecture: i386
Date: Fri Nov 25 09:42:59 2011
ExecutablePath: /usr/bin/gnome-terminal
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
ProcEnviron:
 LANGUAGE=en_ZA:en
 PATH=(custom, no user)
 LANG=en_ZA.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-terminal
UpgradeStatus: No upgrade log present (probably fresh install)