Version: KDE 4.3 RC1 (using Devel) Compiler: From http://ppa.launchpad.net/kubuntu-ppa/backports/ubuntu jaunty i386 version OS: Linux Installed from: Compiled sources Kate forgets to save session even when configured to save upon exit, unless it is set to "ask user first" When don't ask again is selected, kate does remember to save the session. And changes the options to save session upon exit. Unless the session is saved, "Open Recent" also forgets all the previous files. No plugins. Upgraded from standard Kubuntu.
I can't reproduce this here, I've got both "load last-used session on startup" and "save session on exit or session switch" activated under Settings->Configure Kate->Sessions set. Is that the case for you too? I'm guessing right now that you may have "Start new Session" selected in those options, which would explain the behaviour you see. The problem of open-recent-files being session-specific and globally available is discussed in another report (https://bugs.kde.org/show_bug.cgi?id=182759).
Fixed for KDE 4.6. If you use unnamed sessions (i.e. no explicit sessions), all config data is now saved to katerc and reused on startup. *** This bug has been marked as a duplicate of bug 156330 ***