Version: (using KDE 4.3.0) Installed from: Ubuntu Packages Right now, pressing 'P' and 'N' go to previous and next messages, but it skips messages inside collapsed groups. Since there is no way to expand/collapse a group with the keyboard, the correct behavior is for 'P' and 'N' to select the previous / next message regardless of whether the previous / next message is inside a collapsed group. The group should be expanded and the previous / next message should be selected.
Thank you for taking the time to file a bug report. KMail2 was released in 2011, and the entire code base went through significant changes. We are currently in the process of porting to Qt5 and KF5. It is unlikely that these bugs are still valid in KMail2. We welcome you to try out KMail 2 with the KDE 4.14 release and give your feedback.