
Thanks Koldo: you're right I missed some piece for the hurry to post
(but if not in hurry I didn't find the courage to post... )
I hope this zip does contains all the sources.

* the tool is at an early stage and full of bugs
* toolbar
** first three slots allow to insert a shape (class, usecase, actor)
** ABC is for labeling (see connectors)
** then you have four connectors: ISA, DEP(dendency), HAS and AGG(gregate)
** last two ar for deleting (what is selected)
** and for selecting all canvas
* floating-toolbar
** the same toolbar, bu uses the selected canvas as reference
** ISA from the fixed toolbar require specifing both tail and head sides
** ISA from the floating toolbar (if selected on a class) start wiring from the class itself
** the same is for usecase and DEP connector
** when you start wiring in this way you can left-click on the background and a new counterpart
is inserted as head-side
* connectors
** you may connect a connector from/to a shape and from/to a connector
** while wiring a connector you are signalled about the goodness of a given destination
(i.e.: ISA's only work between two classes)
** after wired, a connector can be repositioned: pick-up one side and bring it into another site
** connectors can be dragged by left-clicking them
** polylines are possible with double-click, points are small and become red 
when mouse is near, when red you can move them. To remove points drag them one across the other
or bring them into the head or tail of the connector
** polylines work badly with relative connectors and labels
** to add labels use the "ABC" button and choose an insertion point (...cant change them :-)
** labels can move around
* selecting
** select a shape/connector
** extend selection using CTRL
** to move a selection left-click inside the selection (but not over a shape)
** no canonical dashed-rectangle (I don't like it)
** CTRL-ALT over a shape should select all the incoming/outcoming selectors
* whay all this?
** maybe is just an experiment of c++/ultimate/rational-rose
** but I hope to be able to complete it (in a few months)
** I'd like to build a mini-case... :-)

