The Clear button is far too close to the Post Response button.
Don't compose in the window, but do it off line, then copy and paste. Then, if you hit the wrong button after ten minutes pouring over each word and getting it just right, like I've just done, you will then have a copy to re-paste. It's bad enough having the problem, without having it all disappear down the plughole.
Iv had that problem it maybe an idea to move the clear button a few inches to the right im sure it wont take long to do FE and will stop me when posting from wiping out a 1000 word post in one shot lol.