Session save/load doesn't slider location. Node selection is lost

[BrettJSettle]

When a session is loaded, the slider in the OutputPanel is reset to its default value, which also resets node selection to the nodes that are selected at that value (of heat or rank), losing the selection state from the saved session.

The user must change the slider to the old value to see the same node selection. To fix this problem, we need to either not set the slider position on session load (hide the result panel), or save the slider location with the session.