Editing Contact Type may cause it to become inactive

1. On the Contact Type page

civicrm/admin/options/subtype

if you edit a built-in Contact Type it gets set to inactive (shows up in red in list).

2. If you want to create a new Contact Type (sub-type) based on that changed type, you cannot because the parent type is inactive.

I was able to work around these issues by editing the civicrm_contact_type table directly.

I suspect the root cause of this bug is that the "Save" code is not explicitly setting the "enabled" flag for the contact type record, so when CC saves it it gets set to disabled.