gbz wrote:it was not clear from the question - what are options to interface to Python code from a Instantiations GWT Designer event handler.
No idea. GWT Designer has nothing to do with Python, so you are on your own with that.
There is no such thing as an "Instantiations GWT Designer event handler"; there are just generic GWT event handlers which have nothing GWT Designer specific about them.
This really has nothing to do with GWT Designer. It is just a generic GWT question about how to interface GWT with Python which is best asked in the Google GWT forum.