Undocumented Tip for Chromecast Users!
So, you have pulled up a web page in your Chrome browser, and you click the Chromecast button in the browser to display the video in the tab to the Chromecast. Now, you want to continue to use your PC while the video is playing on your TV. Just go full-screen on the video within the Chrome browser tab, then ALT + TAB. Your TV will show the video, and you’ll be able to use your computer to do something else. Neat!