I had a bug report on Debian about xfapplet plugin. It seems that it's not possible to move or remove an applet from xfapplet plugin starting 4.8.
I have no idea how it works so I'm just forwarding the request.
Downstream bug can be found at http://bugs.debian.org/623830
Mass-reassign all bugs from florian@ to goodies-dev@, thanks for the maintenance work! (and sorry for the bugmail spam..)
Closing all xfce4-xfapplet-plugin (archived/deprecated/unmaintained project).