This is exactly what I was looking for! Dividing a single window into two tabs on the left and right. It's convenient when you need to drag files from one to another and save them, i.e. copy them in one tab and paste them in another. Other extensions look awful, and creating new windows using system tools is an unpleasant method: the bookmarks bar is duplicated (I always have it expanded) and open tabs (I have them on the left, which looks terrible with two windows and takes up extra space). Thank you very much for such a simple and convenient extension!