Customizing mouse functionality

Hi Tiago,
I was wondering if there is a way to customize what happens when a mouse
button is clicked.

In particular I am interested in the following:
1) Disabling the feature that allows user to move vertices around by using
the mouse
2) Any callbacks that might be available when a mouse button is
3) If you could point out the part of your code (name of file/function) that
is being called upon a mouse click (that would be the code that gets the
screen coordinates and from there extracts which vertex has been selected).

Thanks in advance,

You need to take a look at the GraphWidget class:

clicking at the [source] link will show you the source. You will need
either to subclass or modify it to achieve what you want. Sorry, but the
documentation is still a bit scarce in this part, so you will need to
wad through the source code.