In bug 500141 I didn't fix some remaining issues shown in attachment 488954 [details]; parts of the border still do not appear in that testcase. In particular, the algorithm that was patched in bug 500141 is probably fundamentally broken in cases when the rounding of the corner extends past the center of the box, which can happen when adjacent corners are unrounded. Steps to reproduce: load attachment 488954 [details] Expected results: blue/black borders continue around the entire "tilted-eye" shape, though progressing from wide to narrow on each side of the eye Actual results: the parts of the borders that should be narrow are missing

This sounds related to the glitch I was about to report with the repro at http://jsfiddle.net/JVqzL/ (or maybe even the same). If not, I can file it separately. Basically, when a div has a thick border with a border-radius, and overflow: hidden, there is a faint artifact visible where the overflow gets cut off and the border begins.