The fix for bug 1323504 introduced a problem with the camera icon. Because this change involves changing the common.css file, I am using this bug to track the changes. chrome://devtools/content/framework/toolbox-options.xhtml

Previous discussion on bug 1323504 comment 4 and 5.

Comment on attachment 8820222 [details] Bug 1324746 [RTL] Fix camera icon on Toolbox Options https://reviewboard.mozilla.org/r/99746/#review100218 Thanks for the patch! ::: devtools/client/themes/common.css:284 (Diff revision 1) > > .devtools-button::before { > content: ""; > display: block; > position: absolute; > - left: 50%; > + offset-inline-start: 50%; Shouldn't we use offset-block start instead of top to be consistent? This fixes the camera-icon but it took me a while to understand why. The top/left 50% + negative margins is a pattern used for centering absolutely positioned elements, and by itself doesn't need to use logical properties. But here the margin-inline-start: -8px now gets overridden by http://searchfox.org/mozilla-central/source/devtools/client/framework/options-panel.css#111 . Before it was only overridden in LTR, when margin-left ~= margin-inline-start. I don't think the icon position should be adjusted by overriding margins the ::before pseudo, but that's not related to your changeset.

Pushed by ihsiao@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/2122bed2f2ff [RTL] Fix camera icon on Toolbox Options r=jdescottes

Working fine in latest Nightly.

I have reproduced this bug with Firefox nightly 53.0a1 (2016-12-20)on Windows 10, 64 Bit. The Bug's fix is now verified on latest Beta 53.0b3 ! Build ID 20170316045436 User Agent Mozilla/5.0 (Windows NT 10.0; WOW64; rv:53.0) Gecko/20100101 Firefox/53.0 [testday-20170317]