Custom post type / taxonomy approach multiselect dropdown (without search)

Hi!

I noticed that I don’t have a multi-select dropdown option though – only multi-select/search option. Is there a way to apply a multi-select dropdown?
It is possible to disable the search feature via a small custom CSS snippet, so the input for the search gets ignored, and with that it stays a multi select without the search feature:

input.asp_select2-search__field {
    display: none !important
}

I also noticed that the main category doesn’t seem to filter back after selecting the sub-category. I only have one item in place now, but I would expect that to show for both the parent and sub selected.

When the item is categorized in the editor, make sure it is placed both in the parent and sub categories, that is the best possible solution and is future proof. Other than that, you can also enable this option. When enabled, selecting a parent will include items from all children, even if the child has no parent category selected.