Again you're talking about switches. The thread is about normal buttons which have 2 states (the example being given is a button which can be a play button or a pause button depending on the current state). Buttons aren't like check-boxes, switches are. A button triggers an event, check-boxes don't. e.g. on a settings page, you tick all the check-boxes you want first, then click on the Save (or Cancel) changes button - one event for multiple changes. You don't tick a check-box to start playing something, you press a play button (which in this case would then change into a pause button).