Because of the recent auto-crash that's been happening (in Chrome, for me), I switched to IE 9 to play DD. It works decently, except that when DD loses focus and then regains focus (ie. I am using another program) the game pauses for a few seconds before it continues. If, during that time I click on to move my character, even if I don't click on enemies, it will sometimes just outright kill my character. Presumably it interprets one of my clicks as a command to attack a high-level enemy, but I don't really know because all I see is the tombstone result.
This is yet another reason why the game should confirm before letting you make a known-to-be-fatal attack.