Show parent items in hierarchical facet display Taxonomy terms are configured as such:

Parent category 1
- Child category 1
- Child category 2

Parent category 2
- Child category 3
- Child category 4


"Empty facet behaviour" is set to "Do not display facet".

"Flatten hierarchy" is turned off.

"Treat parent items as individual facet items" is turned off.

But the facet display doesn't show the parent items. How do I configure it properly to do so?
Enable the "Index hierarchy" option under your index filters. After enabling you can choose the field(s) for which you want to index the hierarchy. Save. Re-index.

Parent terms will now show in your facet.