Since Q1 2013, the wrapping element of RadButton was changed from an anchor
<a> tag to a <span> because the HTML5 specification does not allow nesting <input> elements into <a> tags. If you are using any
custom CSS cascades based on the <a> tag, they should be changed
to use the <span> tag, e.g.
You should not experience problems in custom styling scenarios when an anchor was not used in the CSS cascade.