Help. Tracking ButtonRelease events

[Philip Derbeko]

Hello.

I'm writing an application part of which is a GUI to draw graphs.
What i want is create verticies and edges between them,
i create vertex by clicking on Button 1 ( taken from Demo/Tkinter/matt
scripts )
and edge created by clicking on Button 3 and dragging the mouse to the
destination vertex.
In order to do it every vertex  binded events ButtonPress-3 and
ButtonRelease-3 ,
the problem i run into is that when i press button 3 and drag it to the
destination vertex,
source vertex gets the ButtonRelease-3 event and not destination.

Am i missing something and how can it be solved ?

Thanks in advance
Philip