[Tracking Requested - why for this release]: RTL issue affecting the first release shipping activity streams. See the screenshot from an RTL build showing the edit UI for the new tab page. The URL field shows the slash at the end of the URL at the left hand of the URL, because the text box is inheriting the direction of the page (LTR). The text box's direction needs to be set to ltr explicitly to avoid this. We do this everywhere in our UI where we display URLs.

So, I guess we need to keep it rtl while it's showing the placeholder text but switch to ltr when there's a value?

Oh. I see the location bar keeps the text right aligned but is ltr.

The alignment should be right-aligned. As far as the directionality goes, the placeholder text may be localized, so that should be RTL in RTL builds, but URLs are always left to right, so they should be LTR.

Beware that without a period or slash or something like that at the end of the placeholder text, you can't tell if the direction of the placeholder text is wrong. So for example, the screenshot you just posted is inconclusive about that. :-)

Fixed by https://github.com/mozilla/activity-stream/pull/3550 to be uplifted via bug 1401418.