I've had to restart my simulation a few times due to inadvertent pressing of backspace with focus somewhere else than an input box. Hitting backspaceĀ takes you back to the main menu, hence resetting the simulation.
I'm sure it's the built-in browser back feature kicking in, but I'm also pretty sure there's some event to prevent it with. Especially within a "proprietary client".
I know saving sims are on the board, but this would be a very appreciated quick fix. 
Great game! KUTGW!