I am looking for a program that is capable of displaying a graph
with nodes and links and with the possibility to edit interactively
the graph : add one node, change one link etc...

Actually, a very _simple_ X11 program would be ok; all I need is to
put some "boxes" (i.e. the nodes ) on a pane and be able to
manipulate them with the mouse (move, add or delete boxes).

Does anyone know if such program is available ?
Thanks for any help !!
