At the beginning, DockBarX was a Gnome2 taskbar applet, working on Mate. But now, it can be also used with XFCE (Xubuntu). It is nice, because it offers icon only application launchers, grouping ability, theme supports, pin applications to panel and more.
This is how you install DockBarX on Xubuntu 13.04.
Add the repo:
$ sudo add-apt-repository ppa:dockbar-main/ppa
Update the repo index:
$ sudo apt-get update
Install DockbarX:
$ sudo apt-get install --no-install-recommends xfce4-dockbarx-plugin
If you want more plugins, install the following packages:
$ sudo apt-get install zeitgeist dockmanager dockmanager-daemon libdesktop-agnostic-cfg-gconf libdesktop-agnostic-vfs-gio
Screenshots from ubuntubuzz:
After you have installed it, right click on XFCE panel and do: Panel -> Add New Items and choose DockbarX -> Add.
Set the basic options of DockbarX, especially the background color to match the color of XFCE panel.
This is it.