Pane element is unique to the Tkinter port. It allow you to slide a partition that changes how much of the elements contained inside are each visible.
Pane does not create any events
There is no item in the Values Dictionary for the
Additional Screen Space
One example use can be found in the Demo Browser. The Listbox Element on the left and the Multiline Element on the right are in a
You can slide the divider between the 2 of them to expose more of one/less of the other. If slid all the way over, then one of the elements will be hidden while the other is completely exposed.
This is one of the more simple examples. You'll find it used in PySimpleGUI when there is a limited amount of screen real estate and seeing the information simultaneously isn't critical. The Log a GitHub Issue GUI is another example.