WASAPI records continuously even without signal

Windows 10, build 1909
Audacity 2.4.2

A feature I use a lot is to record only when a signal is present. For whatever reason this has disappeared: Now Audacity records continuously, with or without signal. I re-installed the program, still same issue.

Settings are:
Host: Windows WASAPI; Playback Device: Speakers Realteck (R) Audio (loopback);
Recording Preferences: Play other tracks and Detect dropouts checked.

Thanks in advance for letting me know what I may have missed.

OK - I got it, and I feel really stupid:
Playing around with the settings, I would - of course - close and re-open Audacity after changes. However, after shutting off the pc and checking this issue again the problem went away. Re-starting the pc was evidently required. Live and learn…

The web browser add-on “flash player” was notorious for doing that. Even after a web page with flash content was closed, flash could still be running and keeping an audio stream active even though there appeared to be nothing playing.