This is a sample OSX project built to demonstrate how to create custom NSAlert that supports the NSAttributedString.
An NSAttributedString object manages strings and permit the use of attributes (url, color, font and kerning etc) that can apply to individual characters or rages of characters in the string.
For more info about this project please check out: http://bertmcdowell.com/posts/2013/nsattributedalert.html