Apologies if this has been reported before.

Httrack does not correctly handle ceratin types of principal domain. 

e.g. if the starting URL is <http://yorkagainstthewar.org.uk> and the
--stay-on-same-domain switch is used (with the intention that
<http://images.yorkagainstthewar.org.uk> is downloaded too), Httrack will follow
links from any site with a domain ending in org.uk i.e. it assumes the
principal domain is org.uk rather than yorkagainstthewar.org.uk

Some might consider this behaviour correct, but I think it limits the
usefulness of the --stay-on-same-domain flag.