Adding Nodes to the TableRowSkin causes class cast runtime exception when sorting on the column header

Attempting to add a Rectangle to the bottom of a sub-classed TableRow for purposes of vertically resizing the TableRow. In order to accopmlish this - I couldn't add Nodes to the TableRow directly but had to add the Rectangle Node to the TableRowSkin instance for the TableRow. All works well - except when clicking on the Column Header t sort the column. The following exception occurs:

java.lang.ClassCastException: javafx.scene.shape.Rectangle cannot be cast to javafx.scene.control.TableCell
at com.sun.javafx.scene.control.skin.TableRowSkin.handleControlPropertyChanged(TableRowSkin.java:91)
at com.sun.javafx.scene.control.skin.SkinBase$4.changed(SkinBase.java:242)
at javafx.beans.value.WeakChangeListener.changed(WeakChangeListener.java:67)
at com.sun.javafx.binding.ExpressionHelper$SingleChange.fireValueChangedEvent(ExpressionHelper.java:181)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:64)
at javafx.beans.property.ReadOnlyObjectWrapper$ReadOnlyPropertyImpl.fireValueChangedEvent(ReadOnlyObjectWrapper.java:154)
at javafx.beans.property.ReadOnlyObjectWrapper.fireValueChangedEvent(ReadOnlyObjectWrapper.java:120)
at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:89)
at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:122)
at javafx.scene.control.TableRow.setTableView(TableRow.java:117)
at javafx.scene.control.TableRow.updateTableView(TableRow.java:294)
at com.sun.javafx.scene.control.skin.TableViewSkin.updateRowCount(TableViewSkin.java:598)
at com.sun.javafx.scene.control.skin.TableViewSkin.layoutChildren(TableViewSkin.java:397)
at javafx.scene.Parent.layout(Parent.java:900)
at javafx.scene.Parent.layout(Parent.java:910)
at javafx.scene.Parent.layout(Parent.java:910)
at javafx.scene.Scene.layoutDirtyRoots(Scene.java:451)
at javafx.scene.Scene.doLayoutPass(Scene.java:424)
at javafx.scene.Scene.access$2800(Scene.java:132)
at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:1750)
at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:292)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:398)
at com.sun.javafx.tk.quantum.QuantumToolkit$10.run(QuantumToolkit.java:330)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:29)
at com.sun.glass.ui.win.WinApplication$2$1.run(WinApplication.java:62)
at java.lang.Thread.run(Thread.java:722)

Self Contained exe File Source Code attached