A DESCRIPTION OF THE PROBLEM :
When keyboard-navigating TextArea using RIGHT and LEFT, on a RTL paragraph, RIGHT is used to go forward and LEFT is used to go backward.

It should be the opposite. LEFT should be used to go forward and RIGHT should be used to go backward. This behavior works well with RTL languages such as Arabic. As examples of text input applying this behavior, Chrome's textarea, Chat textbox on Facebook on the web, text field on Signal Messenger desktop app.

The text selection should be updated accordingly as well.

FREQUENCY :
ALWAYS