How to reproduce: * Try to start a new game * Set two users: Human (player) and Human (spectator) * Press Ok * See how Ok gets disabled * From now on it's impossible to get Ok enabled again (or i could not find it)
The button is only updated once the selection is "set". So as long as the dropdown is active and has not lost focus, the selection is still "pending"; that's why you have to "click" the "OK" button in order to disable it. As soon as you "click" it, the selection loses the focus and the button status is updated. So for you to solve the problem, simply click anywhere (inside the dialogue). However, I too consider this a usability issue which should be fixed.