My "lazy" solution was absolutely treating the symptoms, yes. Which is why I classified it as a lazy one, even. But I feel my first suggestion was exactly what

My "lazy" solution was absolutely treating the symptoms, yes. Which is why I classified it as a lazy one, even. But I feel my first suggestion was exactly what you're suggesting -- immediately register the input and apply the operator -- I just phrased it in terms of what happens to the animation. Also! I certainly feel there are times when letting an animation block your logic is valid. That would be any time when an animation has the UI in a potentially confusing state, such that the meaning of an input is ambiguous. (You should avoid these states as much as possible, of course. And this sort of button-flash comes nowhere even near that category.)