Firefox seems to have trouble correctly placing orthogonal writing-mode floats: it places them on the next line instead of the current one. See, e.g. https://test.csswg.org/suites/css-writing-modes-3_dev/nightly-unstable/html/float-lft-orthog-htb-in-vrl-002.htm https://test.csswg.org/suites/css-writing-modes-3_dev/nightly-unstable/html/float-lft-orthog-vlr-in-htb-002.htm https://test.csswg.org/suites/css-writing-modes-3_dev/nightly-unstable/html/float-lft-orthog-vrl-in-htb-002.htm https://test.csswg.org/suites/css-writing-modes-3_dev/nightly-unstable/html/float-rgt-orthog-htb-in-vlr-003.htm https://test.csswg.org/suites/css-writing-modes-3_dev/nightly-unstable/html/float-rgt-orthog-htb-in-vrl-003.htm https://test.csswg.org/suites/css-writing-modes-3_dev/nightly-unstable/html/float-rgt-orthog-vlr-in-htb-003.htm https://test.csswg.org/suites/css-writing-modes-3_dev/nightly-unstable/html/float-rgt-orthog-vrl-in-htb-003.htm

[Triage 2018/03/23 - P3]

DUPLICATE of bug 1323517 I did not put the links to the submitted tests over there. So, maybe we should resolve bug 1323517 and keep this one as NEW.

The 8 testcases have been imported into dir https://searchfox.org/mozilla-central/source/layout/reftests/w3c-css/received/css-writing-modes - - - - - - Bug 1323517 blocks bug 1380924 ... so maybe we should resolve this bug 1444320 as DUPLICATE and leave bug 1323517 as NEW instead.