xPage CKEdior: how to remove language direction attribute?

in-build CKEditor in xPage (Domino 8.5.3) always add dir attribute to the text container's tags, like P or H2.  

For example:
<p dir="ltr">test</p>

I could change direction "ltr" or "rtl" from the Rich Text Element settings or CKEditor custom config, but I could not remove this attribute at all.

If I use trivial CKEditor, the this attribute absent until I special set up contentsLangDirection property.

So It looks like xPage force this attribute to be set in any case.

Does some one know how to remove it from the in-build CKEditor in xPage ?