When you edit a photo in a separate window, the tools are the same as in edit mode, except for the Size menu that lets you resize the image; it replaces the size slider (Figure 4.6).
The image-editing window doesn't remember its size, so you may need to resize or zoom the window each time.
Editing in windows can be a good way to compare multiple images, or even multiple copies of the same image.
Hide or show the Thumbnail list by choosing Hide/Show Thumbnail () from the View menu.
Use the Window menu to switch to windows you can't see.