When xfce4-taskmanager 1.0.0 is closed by alt+f4 or the window manager close button it remains running with out the gui. However when closed via quit(next to about) it completely closes.
There is an option for this inside the GUI, don't show the status icon.
(In reply to comment #1) > There is an option for this inside the GUI, don't show the status icon. Sorry I missed that since I don't have a tray.