This is now fixed in version 0.1.4. You can wait, and you'll automagically update sometime in the next day or so, or you can pull it down immediately by opening chrome://extensions, ticking "Developer Mode", and clicking "Update extensions now".

Aha! That'll do it. Was the browser really small or something before? It tries to detect how much size there is for a city and use that, so if it can't fit one then I can see how this could happen.

I've got a fix coming for the resizing-with-the-browser thing; sounds that might magically fix this en route. Coming soon, watch this space.

Hmm, interesting, that's very weird. I've spent a while trying to reproduce it myself, but I can't seem to. Next time it happens, can you open the devtools on that page (F12), go to the console and copy out any messages that are there? Hopefully that'll turn something up!

There's an 'idle' API in chrome that I can detect either when nobody has touched the computer at all, over a given period, or when the computer is locked. That's probably the way to go. With that Build Focus will pause automatically and immediately if you lock the machine, or if you just don't touch anything at all for some period.

Any thoughts from people on what duration they think should pass without any input to count as them being away? Too short and it'll happen if you just don't touch the mouse while you're thinking, but too long defeats the purpose. How about 2 minutes without touching your mouse or keyboard = you're away, does that sound reasonable?