As you probably know, all web browsers support opening new tabs, to avoid having to open a second browser window just to access a second, simultaneous, website. This functionality was built as a user experience improvement and can be very useful.
However, let’s say you have a number of tabs opened in your web browser, and want to close all but one. Or for some other reason you want to have one of the tabs currently opened in a different browser window, like you want to compare two webpages, side by side. What do you do?
First of all, to do this the browser window with all the opened tabs cannot be in a maximized state – you’ll see why in a moment. So if it is, restore it to a less-than-maximized state. Do so by clicking on the middle button of the 3 you find in any window’s upper right corner.
Now, with your mouse, click on the tab you want to isolate and drag it outside the currently opened browser window. Then drop it (release the hold of the mouse). Voilà! Now you can close the browser window that contains all the other opened tabs, if that is why you’re doing all this.
P.S.: The process is, by the way, reversible. It works both ways. You can drag a second window back into the first one and that second window will become a tab in the first window.