Description of problem:
KMail crashes when double-clicking on a mail in an IMAP folder.
Version-Release number of selected component (if applicable):
Kdepim 16.04.0 x86_64
I had this issue before with KaOS Linux.
This was solved by installing kdepim-addons. There was a splitt of packages. kdepim-addons are needed now, and not optional.
The issue disappeared with today's update to kdepim 16.04.1.