Known issues in the Plasma 5.1 release.
- XEmbed-based systemtray not supported anymore, for workarounds see http://blog.martin-graesslin.com/blog/2014/06/where-are-my-systray-icons/ http://notmart.org/blog/2014/06/systemtray-plasma-next-and-gtk/
- Override redirect windows (e.g. tooltips, Window Switcher, etc.) are completely translucent on first show, upstream bug: https://bugreports.qt-project.org/browse/QTBUG-39329
- The Meta (or "Windows") key is not recognized as modifier key. Patch merged into Qt for 5.3: https://codereview.qt-project.org/#/c/87615/
- Aurorae window decoration themes might crash the window manager, upstream bug: https://bugreports.qt-project.org/browse/QTBUG-39336
- Text in QML (Plasma Applets and/or Aurorae windows decorator) can get corrupted/turned into boxes: https://bugs.kde.org/show_bug.cgi?id=336615
- Battery monitor tray icon shows battery charging state but not AC adapter state
- Running a Qt 5 application using libvlc crashes that application, apparently because of outdated/non-existing VLC cache. See launchpad bug https://bugs.launchpad.net/ubuntu/+source/vlc/+bug/1328466
- No holidays or calendar events displayed in the Plasma calendar - Awaiting KDE PIM libraries to port to KF5/Plasma5.
- Unable to edit individual locale settings - Can change locale used for setting groups such as currency or date/time, but cannot yet modify individual settings like short date format - Awaiting support upstream in Qt.
- Support for autostarting scripts (like ones setting ssh-agent and so on) in the user's home directory (~/.config/autostart) is missing.
- Environment variables and shutdown scripts are now sourced from ~/.config/plasma-workspace/env and ~/.config/plasma-workspace/shutdown, respectively. Existing scripts should be moved there.
Performance of Plasma 5 is heavily dependent on specific hardware and software configurations and usage patterns. While it has great potential, it takes time to wrangle this out of it and the underlying stack is not entirely ready for this either. In some scenarios, Plasma 5 will display the buttery smooth performance it is capable off - while at other times, it will be hampered by various shortcomings. These can and will be addressed, however, much is dependent on components like Qt, Mesa and hardware drivers lower in the stack. Future releases are expected to bring significant performance improvements thanks to fixes at all levels.