Thank you for pointing me in the right direction.... now I gotta find that function findPostsForThreadView and I'll be on my way to finding the exact sql statement. Would have been nice for a developer to give me the exat sql but your help will do the trick... just takes longer and I was being lazy.
btw: the cause of the oooops, was that the first post_id in the XF_Thfeads table was missing. A quick edit of the thread (after finding "another" first post_id, and bingo, the view now works. Took a bit of work to set last post, first post, date, in xf_threads etc but with 250+ posts in that thread, it was worth the effort.