Often, when you "pop out" a window from Chrome (like a Google Talk chat), it loses its ability to be grouped with other tabs. Here's how to turn a popped out window into a tabbed window so you can de-clutter your desktop.
Often, when you pop out a window, you don't want it to have tabs, toolbars, and extra stuff cluttering up the space. However, for certain things—like the Google Talk client built into Gmail—I'd rather be able to group a few of them together. All you need to do in these cases is right click on the little Chrome icon in the upper left hand corner, hit "Show as tab", and poof! You've got yourself a new, full Chrome window that you can group with other popped out windows (though you'll have to show each of them as a tab before you can do so). I don't know how long this has been hidden away there, but it's nice to have, as those popped out windows can clutter your desktop quickly.
Turn a Popup Window into a Tab in Chrome [CyberNet News]