Automatically place a new problem in the "in progress" status if someone responds

[stevenday]

Currently they have to respond and then change the status manually.

I can't see a situation where a response wouldn't be considered acknowledging the issue, though perhaps I'm missing something obvious. We've just had a support enquiry from a trust where the forgot to change the status until later, and thus the problem's timings were wrong, which this would've helped avoid.