It's important to understand that this corner plugin is pulling off its magic by adding more elements to the page. Specifically, it adds div "strips" to the item to be cornered and sets a solid background color on these strips in order to hide the actual corners of the real item. So if you step back and look at the cornered element, think of there being solid colored divs hiding the true squared off corners of the item you wish to be changed. This helps you understand the inherent limitations of this small plugin. It's best suited for rounding off block-level elements (divs, paragraphs, etc) and may present more challenges when trying to round off inline elements (spans, anchors, etc).