[gardel]

Thanks for the detailed illustrated response. My bookmark preferences are exactly as you suggest, but no success.

What I have found is that the offending bookmark seems to appear in ~/Library/Application Support/Omniweb 5/ServerBookmarks on its own.

With OmniWeb closed, I used Spotlight to search for all occurrences/references to the bookmark and deleted them (usually in cookies.xml and in the directory above).

I then open OmniWeb, and the bookmark appears in the directory again by itself.