Going back to the OP, and your response "Click on profile/look and layout then check or uncheck "Return to topics after posting by default", can you tell me which of those options is supposed to return you to the thread as I have tried both and it doesn't seem to make any difference!

Hi Andrew , the "Return to topics after posting by default" box will need to be checked

Could be that your browsers cache needs clearing.. Try closing it and opening, then see if it then works.
It did not work for me the first time I checked the box.