Add to the action the choice of Python but getting the code from a file

[aperi2007]

In the action setting, actually the python is usable only inserting directly the python code.

But this deny the possible to use a very complex python code to do some very powerful action. Like create a specific form window, import some modules and to do more elaborations.

So would be good to add the choice to link an action to a file with python code and passing it the parameters needed to do the action.