In previous versions, the world search input box and the World Name input box (when creating a new world) were focused. In other words, you could immediately begin typing when opening these menus.
This worked in 19w14a and below, and stopped working in 19w14b.
is duplicated by
MC-154683Create New World screen does not set focus to the textbox when narrator is off.
Resolved
relates to
MC-125097The seed text field is not selected after clicking "More World Options..."