I came accross this question on SO: https://stackoverflow.com/questions/24095549/compute-the-percentage-top-padding-based-on-the-height-of-the-parent-instead-o#24095549 (removed, 10k+ rep needed)
It was quite unreadable but after 5-10 minutes I figured out what the guy meant. So I went on to make edits, pretty much reformatting the entire post. After 5 minutes of work I had something much better, but I couldn't save it because the OP had made some edits in the meantime of just a few characters.
So I clicked
click here to load and all of my edits were gone. I got back what looked like the original post.
As you can understand I felt a bit upset for doing 5 minutes of voluntary work that had to be thrown in the bin, worst of all without warning! The system needs to improve on this in my opinion. At the very least warn that I should copy my changes and paste them after loading.
I would suggest implementing the warning in the meantime while searching for even better solutions. Ideally, give us something that works like SVN, merge additions automatically and let the editor merge conflicts.