Max dropdown list items before scroll

When creating a dropdown item, is there a parameter that will limit the number of items on the list before a scroll bar is enabled, or is there a way to implement a list that can be filtered from a field in the first list item slot?

The issue names no files, tests, or entry points. Start by locating how dropdown items are created and how their list is rendered, then determine whether a scroll limit or filtering behavior is already supported. Done would mean a documented, tested way to limit visible items or filter the list.

Written by the indexing model from the issue text.