Package Manager doesn't work in OpenSolaris 129?

As i’ve got the question twice in last few days through Mail: There is a “bug” in the OpenSolaris 129 distribution that prevents the Package Manager from working. There is a missing package with python 2.6 extras. You can install it with pfexec pkg install SUNWgnome-python26-extras. After installing this package, the Package Manager will start again without any problems.