Opens a new graphical window. Opening multiple windows is useful for tasks like routing pipe, when you often need to view an object from several angles or to zoom in on different parts of a model at the same time. The new window appears on top of all the other windows and becomes the active window.
You can cascade the windows to see only the active window and the title bars of all the other windows, or tile horizontally or tile vertically to see all the windows at the same time. If you change the contents in one window, the other windows that contain the same information reflect the changes automatically without refreshing the view.