Set "Empty local wastebin folder on program exit" to on, Press "Cancel" button Reload "Configure Kmail/Misc" and selection is still set on instead of reverting to previous setting.
I confirm it.
Git commit e6af484bdc1c3cc30e94fc93d8608fb1f756d710 by Montel Laurent. Committed on 05/02/2016 at 12:49. Pushed by mlaurent into branch 'Applications/15.12'. Fix Bug 359018 - Pressing cancel does not undo changes made to "Empty local wastebin..." kmail2 v 5.1.1. FIXED-IN: 5.1.2 M +1 -0 kmail/configuredialog/configuredialog.cpp http://commits.kde.org/kdepim/e6af484bdc1c3cc30e94fc93d8608fb1f756d710