I've never had that happen, although I do tab out, and upon tabbing back into the window, I hit the backspace key, and all that work goes poof. ^^
I can be a bit clumsy, so it happens frequently, although I've been getting better at it. For a while, the forums used to keep all your info after you backspaced, so I became used to still retaining some resemblance of the info. It doesn't do that anymore, however, so backspace now has the power to annihilate your progress-- all at the press of a button.