Created attachment 174261 [details]
mutt compiled with NCURSES instead of SLANG has a buggy thread display.
neomutt does not have the OPTION to select SLANG, added in the patch.
For examples how the bug see the attached two screendumps.
Created attachment 174262 [details]
The buggy thread-display.
Created attachment 174263 [details]
The thread display compiled with SLANG
I cannot reproduce the bug and it would be nice if you provide more inputs about you env variables: locales, encoding etc (LANG, LC_*)
I would prefer not to add a SLANG option if possible but rather fix/understand the issue you are facing with ncurses
A commit references this bug:
Date: Sun Mar 12 14:28:26 UTC 2017
New revision: 435988
Update to 2017-03-06
Add an option for slang support
PR: 217464, 212292
Submitted by: krion, pi