In The plugin you have a separate ui.py. All is needs to do is run
Code:
self.gui.job_manager.launch_gui_app('webengine-dialog', {'module': 'calibre_plugins_your_plugin_import_name.main', 'path': path_to_book})
Then in the main.py file have a function named
Code:
def main(path_to_book):
this can run the actual plugin with the webengine based UI