I've upgraded Fedora 20 -> 21 and new xfce4-power-manager doesn't show up in system tray This means there's no way to quickly switch to "presentation mode" (where display is not turned off after timeout, etc.
Note: looks like systray functionality had been moved into a panel plugin, instead. This is terrible design, since my panel height is 2x or more of normal systray icon -- this means a single plugin takes up at least 4x the space that it should, reducing space available for other plugins/etc.
You can use multi-row panels to keep the icons (launcher and other plugins) small. This helps saving a lot of space.
Wow, that's a new (to me) feature. Thanks for the workaround!
There already is a bugreport asking for the systray to be brought back, consequently marking as duplicate. *** This bug has been marked as a duplicate of bug 11054 ***