Hello, 

as I mentioned on IRC a few days ago, there are some cases where:

  - a thread only displays the first message
  - key bindings do not work at all (except q)

By trial and error, I could nail down the issue to multipart/alternative
support. I had set notmuch to only show the text/plain part of an email
before hitting the bug, and by setting "Notmuch Show All
Multipart/Alternative Parts" to *off* in notmuch-show configuration, the
bug disappeared. 

I'm sorry not to be able to dig further, but I hope this tip will help
users to avoid the issue, and developers to find and fix the bug.

Cheers,

==
hk