(Sorry, I submitted the bug before adding a description. Here it is:) The new Firefox inspector in the dev tools highlights elements inside an SVG foreignObject at the wrong position when the foreignObject is subject to a coordinate transform. To reproduce: load the page <URL: http://www.madore.org/~david/.tmp/foreignobjtest.html >, right-click on one of the elements of the embedded text to inspect it: the highlight is wrongly positioned.
This should be fixed now. Can you please confirm?
Yes, it seems to be fixed in the 12 branch. (I don't suppose there's any chance of the fix being backported to Aurora?)