UI

OK... after going thru all Mithril's code I just figured out that nothing actually happens when calling prop. It doesn't update anything on the DOM tree. So basically, prop acts as a cached key/value store.
And it only makes the desired effect when running after an event and in synchronous code, since Mithril wraps it inside its own start/endComputation.
So the problem is that we are starting a computation befores Mithril has ended its own.