On the settings page,
when the fieldset for a vocabulary is collapsed, it does not show the name of the vocabulary.

My solution was changing line 47 in tagtool.module from:
'#title' => t('Settings for %voc', array('%voc' => $voc->name)),
to:
'#title' => t('Settings for @voc', array('@voc' => $voc->name)),
Its just a minor disturbung bug.