@john.oltman and @attisan I tested the patch from #16 and it worked partially. If the result exists in both View and Attached View, the facet shows the filter option and filters considering the two parts. But if the filter has an option that only has results for the view, the facet filter option is not shown.
To add more information I'll give a real example: I have a view with a Live event list, and an Attached View with a Recorded event list.
If both lists have events in the French language, the filter option French appears and works for both. If the French language is only present in the attached view from the Recorded event list, the filter option is not shown to me because the rule from facet settings that handle the empty filter result behavior is just considering the View, not the Attachment.
Can someone help me with this? I couldn't go further than this yet.