I set the folder pane to have the "Name," "Unread," and "Total" columns, but when I open kmail after closing it, the "Size" column is also shown, and all of the columns are smashed to the left instead of spaced out the way they were before I closed kmail (though I don't know whether the spacing isn't being saved properly or whether it's just getting messed up, because the "Size" column is being added). In case it matters, the other settings I have for the folder pane are "16x16," "Always," and "Automatically, by Current Column."
I am also experiencing this issue. The columns are restored to contain name, unread, total, and size after you restart the Kmail. Irrespective of what you set it to the default column list are restored. Plasma 5.12.6 Frameworks 5.47.0 Linux 4.17.7-200.fc28.x86_64 Fedora 28 Kmail 17.12.3-1.fc28
qt5.11.1?
Hi Laurent, Fedora 28 has Qt Version 5.10.1 according to the kinfocenter.
I also have qt 5.10.1 on FreeBSD.
same issue on fedora 28 Plasma 5.12.6 Framework 5.48 Qt 5.10.1 Kmail 5.7.3
Works correctly on kmail 20.08.3 IMO can be closed