xfce4-windowlist-plugin is a windowlist plugin for the xfce4-panel. 

The menubutton shows the icon of the active window.

Leftclick on the menubutton pops up a configurable window
list (windows on the current workspace or all windows).
Leftclick on the window list activates the selected window,
rightclick pops up a window action menu.

Author: Andre Lerche <a.lerche@gmx.net>

WWW: http://xfce-goodies.berlios.de/