> In this case, input should be buffered and applied to the state of the app after the previous input has been processed.
Yes, and this works best with keyboard-oriented interfaces (which I think is generally much better than touch screens anyways; a lot of software I write is designed for keyboard use because it has this and other benefits). However, it should only be done if the process of the UI is what is expected; if something unexpected occurs then it might be better to discard any pending input. (But, sometimes this "expected" and "unexpected" is not so clear.)
Yes, and this works best with keyboard-oriented interfaces (which I think is generally much better than touch screens anyways; a lot of software I write is designed for keyboard use because it has this and other benefits). However, it should only be done if the process of the UI is what is expected; if something unexpected occurs then it might be better to discard any pending input. (But, sometimes this "expected" and "unexpected" is not so clear.)