Fix: Xfce 4.10 panel no longer expands
After upgrading to Xfce 4.10 from 4.8, I noticed that the clock/notification area no longer pushed to the right edge of the panel. This is due to a change in the Window Buttons panel plugin which no longer expands to fill the available space[1]. To emulate the old behavior, add a transparent separator between the window buttons and the clock/notification area, setting its expand property. Voilla! [1] https://wiki.archlinux.org/index.php/Xfce