Q:
What are “window panes”?

A:
“Panes” are generally referenced when you have a split window, like what you would have in Windows Explorer. The “panes” are the individual sides of the window. In explorer the right side is usually called the “right pane”, the left side is the “left pane”.

Why not simply call them the right and left sides? Well, that would make SENSE now, wouldn’t it??

~Andrew