1. run application attached: there is BorderPane with two TreeView's inside: one is top of borderPane, one is bottom of borderPane.
- bottom TreeView is unaccessible: only several pixels height.

2. remove line 35: pane.setPadding(new Insets(24));
launch application again, try to expand/collapse items in upper TreeView, and try to scroll it's scrollbar to bottom.
after several movements, bottom TreeView become unaccessible due to it's incredible small height.
collapsing of upper treeView does not help.
(see screenshot)