Firefox's mistake is definitely that it isn't handling having outline-offset less than "-min(width, height)/2" in a sane way. (In the demo, width and height are both 100px; it starts do do funny things when outline-offset goes below -50px). That said, I'm not entirely sure that there is a sane way.
IE is totally ignoring the outline-offset property; it isn't implemented in IE.
Firefox's mistake is definitely that it isn't handling having outline-offset less than "-min(width, height)/2" in a sane way. (In the demo, width and height are both 100px; it starts do do funny things when outline-offset goes below -50px). That said, I'm not entirely sure that there is a sane way.
IE is totally ignoring the outline-offset property; it isn't implemented in IE.