Visibility settings saved, but not loaded on settings form

When you edit the "Better message visibility" settings on admin/settings/better-messages, the values get stored in the better_messages variable and the visibility settings work as expected.

However, when you open the form again, the "Pages" textarea doesn't show the previously entered values, but defaults to "*". Of course when you save the form again, the settings you entered before are lost. Sounds like a problem with a #default_value.