Newbie question: I just noticed one of the sites I'm working on has this little 'eye' button at the bottom of the sidebar:
What is it? I can't work out what it's supposed to do…
This only appears when there is "hidden" content on the page (and device view).
Clicking it will reveal any hidden elements (they will still be greyed out, but you can see them), and you can click to "unhide". Be sure to unhide from the other devices if that is what you want. They need to be unhidden for each device.
Also, note that any hidden elements in the header or footer will also be included.