The message .com
from contains these words:

You changed the subject. As many newsreaders display threads by
subject, it will be treated as a new thread in many cases.
(Mine shows it as sub-thread.)

but its upto you what you change its settings to.

That'd depend on the newsreader. Mine goes by subject and doesn't have
the facility to cope with gratuitous subject changes.

--
Skipweasel
Pay no attention to that man behind the curtain.