This is true as an explanation why it happens. I would expect the focused control to be visible and obviously marked (highlight, rectangle, etc). When all that's visible on the screen is the movie, or when the last thing you did was hit something to play the movie, the app should switch focus to whatever control needs to have it for space to play/pause. This is already a solved problem, many console video players do this, Netflix does it, etc. It drives me nuts that something so trivial in an area of an app that is (comparatively) so simple, remains broken for so long. It is not really important, but it destroys the potential for the app to feel natural and (in Apple parlance) beautiful to use.