How to use TAB key to indent a line in input textfield

I see there are "TextFormat.tabStops" and "TextField.tabEnabled";

I put on a multi-line input textfield in my movie. However, I can not use TAB key to indent a line. When I press TAB key, it just makes my focus shift to other buttons.

Is there a "wantTab" property for textfield ?

If TAB key can not input "\t", then why do we need to set tabStops ?