Effect: When you change a volume from *inside* the Mixer, it's modified successfully but the Panel icon doesn't reflect the changes. Both the Mixer icon's visual meter steps (the blue lines) and tool-tip are kept with the old settings. However the volume is really changed, as can be seen using FreeBSD's /usr/sbin/mixer or any similar utility. Using the mouse wheel directly on the Panel icon works perfectly, though. How to reproduce: 1. click on the Mixer's icon 2. move the slider of the default Mixer track (the one shown in the Panel icon) 3. quit
I forgot to mention this: if you right-click and enter the plugin's Properties, then click "Close", the Mixer's Panel icon is finally reloaded with the new settings. This should of course be the default behavior or the Mixer's *Quit* button.
Also affects Ubuntu here: https://bugs.edge.launchpad.net/xfce4-mixer/+bug/570993
With version 4.9.0 the panel applet now automatically configures itself on startup so this should be fixed now.