drag2share: YT Background Search for Chrome Explores YouTube Without Leaving the Current Video [Chrome Extensions]
Chrome: Watching YouTube videos almost always generates ideas for more videos to watch, but initiating a new search means closing the current video. With YT Background Search, you can look up what you'll queue next without closing the currently playing video.
The extension splits the YouTube page apart when you type in a search and shows you the results at the top of the page while your currently playing video continues. That's all this extension does, but since it runs unobtrusively in the background and works its magic automatically, you'll never notice it's there.