Version: (using KDE 4.3.4) Installed from: Debian testing/unstable Packages Reproduceable Bug: * select folder * switch to "Threaded View" * mark one mail * use "SHIFT+<ARROW DOWN>" to mark mails (e.g. to delete later on...) * if the is a separator like "Thursday" or "Yesterday", you need to push the arrow key two times to select the next mail. Occasionally the separator is handled like a mail, but the expected bahavior is to mark the next mail with only one click.
I can confirm it in kmail2
Seems to be gone in KMail2/KF5.