STR:

1. Set media.videocontrols.picture-in-picture.video-toggle.mode to 1.
2. Visit https://www.cbc.ca/player/play/1785729091945
3. Click on the "Play" button on the video
4. Hover the video to reveal the toggle, and then click on it:

ER:

PiP should open and the video should continue playing.

AR:

PiP opens and the video pauses.

I think the code that detects and suppressed the click event isn't working exactly as intended.

This makes it easier to avoid a race where layout of the toggle was sometimes
out of date during the mouseup and click events because the underlying UAWidget
had changed. Instead, we wait until the last event (mouseup in the case that
the mousedown occurred on a different target, click in the case that the
mousedown occurred on the same target), and only then trigger Picture-in-Picture.