To identify what is going on, set a breakpoint in the client side code for example here:
./sites/assets/js/form.min.js: function () { return this$1.script_manager.trigger(“before_save”); },
Follow this howto Chrome DevTools | Chrome for Developers
This notes events to check out
To set a breakpoint on the server add this line import pdb; pbd.set_trace()
Here’s how 9. The Python Debugger
./apps/frappe/frappe/model/document.py: def run_before_save_methods(self):
./apps/frappe/frappe/model/document.py: - validate, before_save for Save.
./apps/frappe/frappe/model/document.py: self.load_doc_before_save()
./apps/frappe/frappe/model/document.py: self.run_method(“before_save”)