A quick actions pop over can be used when you want to provide actions for items that have competing internal targets. It has to be triggered from a distinct visual target, so the user knows that there's something he can do with it. Make sure the pop over is not blocking the screen like a traditional dialog, but popping above or below the item. Only use the most important and obvious actions in the quick actions pop over. For other contextual actions you can choose to add a context menu.