User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv:1.9b5pre) Gecko/2008031304 Minefield/3.0b5pre Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv:1.9b5pre) Gecko/2008031304 Minefield/3.0b5pre The new way of rendering borders makes the shared (dotted) border between two objects look like it was solid (at least when set to 1px). This does not happen with border-style: dashed. Possibly related: #379303 I'm going to upload a testcase for this. Reproducible: Always Steps to Reproduce: n/a Actual Results: The shared border (border-bottom of the upper div and border-top of the lower div), both styled as 1px dotted, is rendered as if it was solid. Expected Results: Border is being rendered dotted.

Confirmed on Windows XP, latest trunk. This regressed in the last days of April 2007, so this is probably a regression from Bug 368247.

as of today, i can't reproduce the bug with the above testcase, but this one (using an unordered list) still shows the bug.

I'm not sure this should be considered a bug -- I don't think we've ever made promises that dotted borders will always start at the same offsets or something across the entire page (nor does CSS require us to). Since the borders are explicitly overlapping here, the solid line is indeed unintended, but shouldn't be unexpected.

In both testcases, the rendering of the overlapped dotted borders can be persuaded to be, hm, not a simple line of perfectly round dots, by messing with the zoom level. Visually, you can get solid lines, dotted lines, dashed lines, odd zigzag thingies, and some others. I agree this is not necessarily a bug, but will see if I can't make it go away as a side effect of addressing bug 379303 / bug 19963.

User Agent Mozilla/5.0 (X11; Linux x86_64; rv:48.0) Gecko/20100101 Firefox/48.0 Build ID 20160414030247 This still reproduces on latest Nightly (48.0a1) with the testcase from comment 6. As this being an old bug we should choose if we consider it valid (and should be fixed) or if it can be closed as Invalid. As a note, it works as expected on Chrome.