Headers of mail in the current folder can't be searched. Right-clicking on the folder and selecting "search" only gives "enable nepomuk", but that "enables full-text search" of bodies. I have no interest in nepomuk, it's bloated and far more trouble than it's worth. And it's not needed for searching headers. Unfortunately the index/quick search (whatever it's called) leaves a few things to be desired, its mode of operation being one of them (is it "anywhere in headers"? who knows) , but almost always I want to know name or email address in either sender or receiver, so it's of not much use. And when I enable all that nepomuk stuff in desperation, kmail still says "not running, enable in system settings". Kmail does not have useable email header searching. Reproducible: Always
This bug has only been reported for versions before 4.14, which have been unsupported for at least two years now. Can anyone tell if this bug still present? If noone confirms this bug for a Framework-based version of kmail2 (version 5.0 or later, as part of KDE Applications 15.12 or later), it gets closed in about three months.
Just as announced in my last comment, I close this bug. If you encounter it again in a recent version (at least 5.0 aka 15.08), please open a new one unless it already exists. Thank you for all your input.