cmake-gui: 3.19.1 does not auto-complete source/build tree selection

While typing in the directory selection boxes in the main gui page, it's supposed to pop up suggested completions one can chose with arrow/enter keys.

This worked in 3.18.5. It doesn't work in 3.19.1.

EDIT: Completion using 3.19.1 works if one types the path from the root, but not if one edits an existing path in the field. Completion using 3.18.5 works for both cases.