Currently, the caret in <textarea> is affected only by the CSS direction, even for unicode-bidi:-webkit-plaintext. It should work in an LTR manner in an LTR paragraph and in an RTL manner in an RTL paragraph, as determined by -webkit-plaintext.
1. Navigate to data:text/html,<textarea style="unicode-bidi:-webkit-plaintext; direction:rtl"></textarea> or data:text/html,<textarea dir=auto>א!</textarea>
2. Put the focus in the textarea, press End, and press Enter.
3. Type "hello!" and note that the text is rendered correctly LTR, i.e. as "hello!" and not as "!hello".
4. However, note the visual location of the caret while typing. It stays to the left of the "h" throughout. It should be to the right of the last character typed in.