Disable pause on losing focus

When the window with the game loses focus (e.g. you Alt-Tab somewhere), the game is automatically paused. Can I disable this behavior? (I need to test some effect that takes a long time and don't want to waste this time, so I'd rather switch to some other window and do something else while I'm waiting).

So, I guess there is no hidden option that can be set in the ini file but not from the menu? I thought so (though still hoped for it) since I couldn't find anything that looked like it in the ini file. It seems I'll have to make a feature request and hope for the better.

It seems I was too hasty, there is such an option, and it is accessible through menu too, though it is cleverly named so that you probably won't find it when looking for something related to pause Thanks to Rachael for the answer: viewtopic.php?f=15&t=74425&p=1210587#p1210582