Hello Olivier, thanks for your answer.
I have overriden this function in all my edit parts but unfortunately, it
doesn't seem to be called when I open an existing diagram ("File" ->
"Open..."). I'm sure that the diagram that is loaded contains nodes for
which I modified some properties.
This function is correctly called when I change a property, but not when
the diagram is loaded from a file.
I was thinking of putting that code in the active method of my edit part
but I have no idea how to retrieve specific properties of my node from
within the edit part. And I'm not really sure if this is the best place
where to put this code.