gpiv throw gtk-critical on closing

[Sasa Paporovic]

I am on Ubuntu12.04 64bit updated to 7.4.2012.

Reproducing:
1.Installing gpiv
2.open terminal
3.typing gpiv -> program starts
4.closing gui of gpiv with crsoo in left upper corner(system ability)
5.See on terminal:

(gpiv:19768): Gtk-CRITICAL **: gtk_widget_unref: assertion `GTK_IS_WIDGET (widget)' failed

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: gpiv 0.6.1-2
ProcVersionSignature: Ubuntu 3.2.0-22.35-generic 3.2.14
Uname: Linux 3.2.0-22-generic x86_64
ApportVersion: 2.0-0ubuntu4
Architecture: amd64
Date: Sat Apr 7 17:26:39 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64+mac (20120328)
ProcEnviron:
 PATH=(custom, no username)
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: gpiv
UpgradeStatus: No upgrade log present (probably fresh install)