GTK stock item not defined

According to GTK documentation, <http://www.gtk.org/api/2.6/gtk/gtk-Stock-Items.html#GTK-STOCK-MEDIA-FORWARD:CAPS>, the stock media play icon is supposed to have both a left to right and right to left variant. There only appears to be the left to right version defined in this theme.

gpredict uses both the left to right and right to left variants.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: humanity-icon-theme 0.5.3.10 [modified: usr/share/icons/Humanity/actions/24/media-playback-start.svg]
ProcVersionSignature: Ubuntu 2.6.38-10.46-generic 2.6.38.7
Uname: Linux 2.6.38-10-generic i686
Architecture: i386
Date: Fri Jul 15 23:27:52 2011
InstallationMedia: Ubuntu-Netbook 10.04 "Lucid Lynx" - Release i386 (20100429.4)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: humanity-icon-theme
UpgradeStatus: Upgraded to natty on 2011-06-15 (30 days ago)