Hi Sophie
You can not “click” a button, but you can call an action for example a nanoflow or microflow.
Take the source code
Instead of call refresh you can call an actions
https://apidocs.rnd.mendix.com/8/client/mx.data.html
https://apidocs.rnd.mendix.com/8/client/mx.data.html#.callNanoflow
To provide a microflow to the widget you have add a prop to the XML
https://docs.mendix.com/howto/extensibility/use-xml-widget#5-2-7-microflow
The feature is now available in the App Store https://appstore.home.mendix.com/link/app/47782/ version 1.1.0
Cheers, Andries