I'm trying to set up a CHILD of a set size, that will swap out PANES.
The child size is, for example, 500x500, but the panes may be 500x1000 (i.e. longer).

How would I make it so that when I display such panes, the control the pane is being shown in grows a scrollbar?

~Thus allowing my overall window to remain the same size, and still display everything.

On the Pane Window, Edit the window, goto Options Tab, and change the Scrolling mode to Vertical.
That should be the only problem down there for the Scrollbar to not be showing up.
In response to Neo Rapes Everything
Ah! Thank you, that solves the problem.
But I distinctly remember setting that to vertical!!
~Must have un-done my selection when i clicked the other tab options. Hate how the skin does that.