We get a nice little file collision during the upgrade path. /usr/share/icons/hicolor/48x48/apps/xfce-edit.png /usr/share/icons/hicolor/48x48/apps/xfce-filemanager.png /usr/share/icons/hicolor/48x48/apps/xfce-games.png /usr/share/icons/hicolor/48x48/apps/xfce-graphics.png /usr/share/icons/hicolor/48x48/apps/xfce-internet.png /usr/share/icons/hicolor/48x48/apps/xfce-man.png /usr/share/icons/hicolor/48x48/apps/xfce-multimedia.png /usr/share/icons/hicolor/48x48/apps/xfce-printer.png /usr/share/icons/hicolor/48x48/apps/xfce-schedule.png /usr/share/icons/hicolor/48x48/apps/xfce-sound.png /usr/share/icons/hicolor/48x48/apps/xfce-terminal.png /usr/share/icons/hicolor/48x48/apps/xfce-unknown.png /usr/share/icons/hicolor/48x48/apps/xfce-utils.png The most apparent solution would be to make libxfcegui4-4.4.0 block < xfce4-panel-4.4.0.
Fixed in CVS.