For people who doesn't know about this, DCW has a thing called Autosave feature which saves your inputted reply in the reply box from time to time on separate threads. So in case of an accidental exiting from DCW while you are editing and typing in a reply on a thread and you wrote a very long post, you can recover it with the said feature.
Anyways, here's a screenshot of it:
If you see that thing, that means your draft post has been saved. Also, you'll notice that the last auto saved time changes as you type in more content on your post and as time passes by.