Hey Stephan,
If I understand correctly, the “Listen to widget” functionality is kind of “broken”, because you press the nanoflow-button and therefore the item is not getting selected?
As workaround, you could create a (non-persistent) pagehelper having an association to the item that needs to be selected to be shown. Then you could set that association in your nanoflow and show it in the sidebar based over association.
Maybe this helps!
Kind regards,
Johan