Make the XFCE panel energy efficient / power management aware
When the screen saver kicks in, the monitor is turned off via DPMS or there's a full screen application running which hides everything, all the applets on the panel continue to listen to timing events and update themselves unnecessarily.
Would be great if panel and everything on it "hibernated" when it's hidden.
At the same time I've noticed that the DateTime plugin after resuming from software suspend doesn't update itself momentarily, so you may observe the wrong time for up to 59 seconds.