Unexpected thing appeared in <textarea> + scrollbars

Question

The white rectangle item on the bottom-right is disturbing my page's UI,
What is it, how can we remove/ hide/ edit it's color.

https://code.sololearn.com/WDzY1dD95aKC/?ref=app

Answer 1

::-webkit-scrollbar-corner{
background-color:var(--item-background);
}

Source: https://stackoverflow.com/a/28075981/12485639

Answer 2

If you like you can build in an auto-scroling function as well as monitoring for scroll length similar to this example:

https://code.sololearn.com/WJqv5tPfKuso/?ref=app