STR: 1. Visit https://hg.mozilla.org/mozilla-central/raw-file/75a32b57132f8cba42779555662a057a0416a313/layout/reftests/w3c-css/submitted/flexbox/flexbox-align-self-baseline-horiz-001a.xhtml 2. Right-click the lower blue dotted area (the second flex container) and chose "Inspect Element" 3. In the layout panel, under "Overlay Flexbox", click "div.flexbox.lastbase" 4. Compare to what happens if you pick the other (higher up) flexbox. ACTUAL RESULTS: There's no visual indicator for the lower flex container's baseline alignment position, but there is one for the upper flex container. EXPECTED RESULTS: Consistent behavior on visual indicators for baseline alignment. (Both flex containers use baseline alignment for their items, but the first one uses first-baseline whereas the second one uses last-baseline.)

(Note: you have to enable the pref "devtools.inspector.flexboxHighlighter.enabled" for this section of devtools to be available)

Hmm, it looks like we don't draw the baseline alignment line overlay anymore (at least, I'm not seeing it when activating devtools). gl, is it still there but now requires another step to show? (in which case, this bug is potentially still valid) or did we remove it? (in which case, maybe this bug doesn't serve a purpose anymore)

(I'm guessing this UI is just suppressed for now and will be reenabled [potentially still with this bug] when we get to focusing on alignment inspector in bug 1492055 & friends)

Yes, we are not focusing on shipping alignment with this release.

Thanks. Looks like the alignment stuff (and the baseline overlay in particular) was disabled for now in Bug 1472561. FWIW, I verified that this bug & bug 1468862 are both still reproducible in current mozilla-central if I revert that patch locally. (Not surprising, but just mentioning for the record, since I got a ping from QA about retesting this bug earlier today.)