When using border radius on a parent element, I believe the assumption is it should clip all child items, especially if it's set as overflow: hidden;
For some reason this does in fact work until the parent element is set to position: relative;
I don't believe this is intended behavior, correct me if I'm wrong.
testcase is in the URL field.
I can confirm this. Tested with 13.0.782.20 dev. Firefox renders it correctly (if the -webkit prefix is removed).