Sometimes it is helpful to see the wireframes of different objects on your page as some objects are layered below others.
X-ray mode applies a temporary grey overlay onto the editing page and shows the wireframes of all the objects on the page in white to help identify them more easily.
To enter X-ray mode in the editor use the shortcut command CMD+OPTION+X (on a mac) or CTRL+ALT+X (on Windows)
X-ray mode off:
X-ray mode on: