The following two tests fail because there's a horizontal scrollbar shown in the tests but not in the references: imported/w3c/css/css-multicol-1/multicol-fill-auto-block-children-002.xht imported/w3c/css/css-multicol-1/multicol-nested-column-rule-001.xht I guess we can modify the test to suppress scrollbars?
/multicol-nested-column-rule-001.xht [Passes in STP184] - https://wpt.fyi/results/css/css-multicol/multicol-nested-column-rule-001.xht?label=experimental&label=master&aligned While 'multicol-fill-auto-block-children-002' still fails in STP184 and also in Chrome Canary. https://wpt.fyi/results/css/css-multicol/multicol-fill-auto-block-children-002.xht?label=experimental&label=master&aligned Analyser - https://wpt.fyi/analyzer?screenshot=sha1%3A38af57470a2174d3f474539c8b2f34eca6180abe&screenshot=sha1%3A7f7cc6e70351fff9008c884d7cd1775e15e27ac9