This is a problem in the completions system since 2005f2e (Let completion functions set the
match_required state., 2009-05-08)

If the completer fails (say because it couldn't load a file and it threw an error), then the
match_required doesn't get passed through.  So, xpath webjumps will report errors properly when you try
to complete, but when you press enter it will follow a bogus url.