Disabling module does not remove widget from node edit form

After I have disabled the Content Type Selector module, its widget still appears in the node edit form. Clearing Drupal cache didn't help. One wrinkle is that this is on a dev site where the database has been manually copied from the live site. The live site never had Content Type Selector installed.

I am having difficulty replicating the issue on a third test site. I installed Content Type Selector and created a couple of new content types, each with a CCK text field, but the Content Type Selector widget will not appear on the node edit form.

What am I missing?