You'll undoubtedly be ecstatic with Safari 3.0 in 10.5 then, as this is precisely how it is going to work (other than the purple outline). I don't know if that is a part of the interface that OmniWeb can inherit through WebKit but, if it isn't, I hope it is something that is inherited through the OS itself as it does make finding things much, much easier.
http://www.appleinsider.com/article.php?id=2111