Searching for how that might happen using the backspace key I tried all the combinations using Ctrl, Alt and Shift. Then went down the "F" keys and hit something that I now can't duplicate were the backspace key and a function (F) key deleted everything I'd written.

If you're typing on a mobile phone, there might be a problem that's causing a "delete all" command to occur. Obviously, that command is there somewhere. I just tipped it on my PC. I'll see if my tech adviser has any suggestions.