What is the problem?

The feature implemented in T261430 does not work on Safari.

In one case, after using the watch star, tabbing continues further down the page, ignoring the dropdown.

In another, the tabbing first goes to the survey (which you get on each page of beta) and then to the expiry dropdown.

These were all tested on https://en.wikipedia.beta.wmflabs.org.

Thanks to @Jpita and @Mhurd for finding this.