Enter keypress does not work properly in mutt after upgrade to 18.04

I just upgraded from 17.10 to 18.04. Looks good. However, mutt no longer works properly.

Specifically, within mutt, in the index view, hitting Enter no longer opens up the email message.

I verified that Enter is working on my machine in all other applications. Also, within mutt when I change mailboxes, Enter works just fine to select the other mailbox. But, for some reason, within the index view of mutt, Enter produces no response from mutt. I have not changed anything about mutt, or my muttrc. The only change in the past few days was the upgrade to Ubuntu Budgie 18.04.

Any thoughts?

The Space button works in mutt, in the index view, to display messages. Perhaps I was mistaken that Enter was supposed to do the same thing.

For now, let’s call my issue closed.