A document referred to someone working as a panebeater. I speculated whether that had something to do with making glass, or breaking it. I had never previously considered that panes and panels are related, from Middle French pan and Latin pannus, a piece of cloth. Panels are, literally, little panes.
Nowadays, a pane is almost certainly glass, though Dictionary.com also records it in connection with wood panelling, while a panel can be wood, metal, plastic, glass or people. We probably say pane of glass and glass panel, though, while wood panel and panel of wood etc are probably interchangeable. (Note expert panel and panel of experts.) Panels overlap with boards, in referring to both the pieces of wood and the people who sit at them.
Never Pure and Rarely Simple 