Currently when you edit a post the popup window thingy shows you a preview of what the post will look like. You can also close the window and save the edit as a draft and come back to it later... this is where my feature request would be the most helpful, so that I can see the diff between the original post and the edit to help remember where I was or if I actually finished the edit and forgot to post it. It would also be handy when making an edit to a code block to fix a bug or something