5점중 4점 받음

It seems I can't actually post a new review, only edit the previous one so I hope this actually gets read.

Yes, Developer, you are correct that in Gmail the messages themselves don't change position and this is as it should be but the latest date received is sent to the top. Does this make more sense?

이 검토는 현재 부가 기능의 이전 (0.6) 버전에 대한 것입니다. 

You're not missing anything - that's by design. When a new message arrives this extension will bubble the entire thread to the top of your inbox, but the thread itself will remain in the order the messages were received (with the newest at the bottom). I've never seen a threaded view operate differently (gmail does the same thing). Thanks for the feedback though. :)