How can you delete an item in url history?

I have quicktime 5.0.2 for mac os9. I chose file/open URL, and typed in a website. The file was not a file type that quicktime could recognise. Now when I try to type in a URL, that one is the default. I typed another one, and that became the default, but the faulty one still remains in the history to the right. Where is this information stored, and how do I delete it?