Using the default Boost theme, if you install a custom profile field plugin that has a name alphabetically higher than the highest included in core (i.e. higher than profilefield_checklist) it will clip behind the title bar which makes it not able to be selected and not visible.
This also only happens when there are no categories (e.g. a fresh site). When categories are present, it does not clip, since the list sits slightly lower.
See attached image, the DOM elements of two profile fields starting with the letter A are clipped behind the white bar.
This is on Firefox 109.0 (64-bit) Ubuntu
- Ensure there are no custom profile field categories
- Install a custom profile field plugin start with letters A or B (so that it sits above profilefield_checklist)
- Go to settings -> user profile fields
- Click on "create a new profile field"
- Confirm that the list clips upwards and the profile fields sit behind the white bar