FXML-LoginDemo : Exception in certain case

Launch FXML-LoginDemo

Login as "demo" & "demo"

Let's try to add address at first, leaving other fields blank.
For this, click in TextArea for address...

And you'll get such error:

///////////////////////////////////
java.lang.ArrayIndexOutOfBoundsException: -1
at java.util.ArrayList.elementData(ArrayList.java:371)
at java.util.ArrayList.get(ArrayList.java:384)
at com.sun.javafx.collections.ObservableListWrapper.get(Unknown Source)
at com.sun.javafx.scene.control.skin.TextAreaSkin$ContentView.layoutChildren(Unknown Source)
at javafx.scene.Parent.layout(Unknown Source)
at javafx.scene.Parent.layout(Unknown Source)
at javafx.scene.Scene.layoutDirtyRoots(Unknown Source)
at javafx.scene.Scene.doLayoutPass(Unknown Source)
at javafx.scene.Scene.access$2800(Unknown Source)
at javafx.scene.Scene$ScenePulseListener.pulse(Unknown Source)
at com.sun.javafx.tk.Toolkit.firePulse(Unknown Source)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(Unknown Source)
at com.sun.javafx.tk.quantum.QuantumToolkit$10.run(Unknown Source)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(Unknown Source)
at com.sun.glass.ui.win.WinApplication$2$1.run(Unknown Source)
at java.lang.Thread.run(Thread.java:722)
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

It's hard to say for me, is it a naive sample's code bug, or inner FX-bug, but behaivour is highly inappropriate.

BTW, if you'll try to move into address's TextArea with subsequent <TAB> pressing, this bug is not appear.