Fixed header works, but fixed footer isn't showing when testing the prototype

[Gleb]

Fix Position when scrolling causes frames to disappear

If you set constraints correctly, nothing will disappear. Constraints control which side of the screen is used when fixing the content relative to it. So if your item is somewhere at the bottom of the long scrolling list (y = 1500 for example) and you set its constraints to Top — it will be fixed relative to the top, at y = 1500, which is outside of the visible screen.