First, XFCE is a very worthwhile effort. Definitely fits for those who don't want the Gnome/KDE bloat and who also don't have the patience to configure every single keyboard combination in FluxBox. Thanks to the developers for their time.
The keyboard plug-in seems to be unstable. I have three layouts configured. At times the plug-in disappears ("plugin keyboard layouts unexpectedly left the panel"), other times the key assignment to change layouts disappears. I've tried the setxkbmap command, but that doesn't bring the plug-in back to life.
Any suggestions to keep the keyboard plug-in stable, or how to recover when it dies?
Please try the latest version (0.5.4.1) which should fix most (if not all) of your issues.
Thank you for the advice. I couldn't compile it from source (configure: error: The intltool scripts were not found. Please install intltool.) I'll wait for the deb from Ubuntu. Glad to hear a fix is available.