Version: (using KDE KDE 3.3.0) Installed from: Gentoo Packages How to reproduce: Turn global threading (option in settings) off. Go into some folder, and turn threading on from the Folder menu. Then turn on global threading again. Return to that folder. For me, that folder is no longer threaded, but when I look at the message menu, the threaded option is checked. If I uncheck it, and then check it again, it works.
I can confirm this, but only if you start with folder->threading enabled.
This problem still exists in kde 3.4 beta1 (3.3.91), kmail 1.7.91 1. start with Folder->threading enabled 2. turn threading off globally in the options 3. turn threading on globally in the options --> folder will not be threaded anymore This only applies to the folder you were viewing when changing the global options.
I have the same, or similar, problem in KDE 3.5.1 in SuSE Linux 10.1 beta. Generally, the global threading option in the KMail Settings works in a very confusing way. It more or less seems to toggle the setting for all folders, except for the very first time, in which case it seems to do nothing at all. (A window pops up, asking the user to confirm to override the settings of all folders, but in fact it does not do anything.) I think this could be the same case as bug #33815, which is marked as CLOSED but unfortunately not fixed.
In fact, when I watch the behavior closely, it seems to be something different than a pure toggle. When all folders are in un-threaded mode, and I enable the global threading switch, the folders get into some transitional state; the view looks like threaded (there are thread markers at the left) but no thread structure appears, as if every message was a thread on its own. So, this may not be a bug in view toggling, but somewhere deeper; it seems that the view is set correctly but the internal ordering of messages does not change. Hopefully this helps in finding the bug.
Consider this obsolete since the UI revamp in KDE 4.2. Please complain when I'm wrong.