Latest Drush cannot 'pm-uninstall toolbar'

This is not a massive problem because toolbar can be manually uninstalled but...

previously with drush all-versions-4.x-dev I have been able to successfully disable and uninstall the toolbar that comes with Drupal 7.

The two latest versions that I have used (10th July and 13th July) allow me to: drush dis toolbar...OK

but then error when I drush pm-uninstall toolbar saying:

'To uninstall toolbar, the following modules must be uninstalled first: standard
There were no modules that could be uninstalled.'

1) What is standard?
2) Any ideas what has caused this small hiccup to a fantastic module?

Thanks