📝 Summary
In the Boost theme (not classic) there is an issue with date pickers/calendar popups being fixed in position.

🎬 Steps to Reproduce
Login to the platform as an admin and access the Browse list of users screen (or bulk user actions). Click 'Show more' to view all the filters and find one of the filters with a date picker. Tick the box to enable the date picker then click the calendar icon on the right hand side.

In the classic theme the popup remains fixed as you'd expect when scrolling on the page:

However in Boost based themes if you were to click the calendar icon and were scrolled to the top of the page (so the calendar icon was near the top of the screen) then the calendar icon may be chopped off/hidden. And scrolling doesn't resolve the issue as the calendar is fixed. You can easily forget which field the date picker is actually for as well.

✔️ Expected Behaviour
As in the Classic theme, the date picker popup should remain inline above the correct field (just above). See video for details.

📓 Additional Details
See video attached (Added after ticket creation).