Sorry, this is the only demo for URL detection. All complicated logic is in URLScan.pas, copy it to your project.
This file in demos has bug in processing of Unicode text, the fixed version is here:
http://www.trichview.com/support/files/urlscan.zip
Yes, this demo does not implement removing link after user removed "http://" or "
www.". But I just looked in MS Word 2003 and OE 6 - they do not do it as well.
As for updating tag - yes, this is not implemented yet. I requires additional functions of TRichViewEdit that will be implemented in one of future updates (you can update tag in OnItemAction event, but there will be problems with undo)