[Mirroring] MX RichTextEditor buttons incorrectly reverse labels when setting layoutDirection to rtl

Found in 4.5.0.14095

Steps to reproduce:
1. Compile and run attached MXML file.
2. Change layoutDirection to "rtl"

Actual Results:
The bold button label "B" is backwards.
Same with the italic button "I" and underline button "U".

Expected Results:
Should those button labels be reversed?
Even if i set the layoutDirection to "rtl" and then select some text and set it to italic, the text oddly seems to italic the same direction as when the text was LTR.

Workaround (if any):
Explicitly set the bold, italic, and underline buttons to always keep LTR type labels:

ret.boldButton.layoutDirection = "ltr";
ret.italicButton.layoutDirection = "ltr";
ret.underlineButton.layoutDirection = "ltr";