Ah, this reminds me of a lovely Mac-only thing that isn't featured in this article: you can drag and drop the little icon in the title bar! For instance, you ha

Ah, this reminds me of a lovely Mac-only thing that isn't featured in this article: you can drag and drop the little icon in the title bar! For instance, you have a PDF opened in Preview and want to send it? Just grab the icon and drop it onto Mail's icon.