Figured Bass duration and continuation lines not working / No mixer window.

Mac 13.6.6, Muse Score 4.4.1, latest build.

Pressing control or command plus 5 (6, etc) does not advance the cursor. It does nothing.
Also, pressing underscore only shows a visible continuation line while the cursor is active. Pressing the spacebar to advance the cursor makes it disappear. As above, pressing command or control plus a number does not extend the line. I can only type a separate continuation line under the next note, but it does not connect with the previous one.

Am I missing something? I read of a similar issue about 9 months ago, but they said it had been fixed.

Also, I can't see the mixer window, even though it says it's open. Pressing the mixer button at the top does nothing.

Thanks in advance.