Consider loading the attached NB project. Run it and you get the Ticketing demo up.
In the tree view on the left click on "Project1".
Click on the top left button "New Ticket".
In the details part (bottom right) click on the TextArea below the label "Description:" then you get the exception below.
From now hit a character on your keyboard and you get the second exception.

java.lang.ArrayIndexOutOfBoundsException: -1
at java.util.ArrayList.get(ArrayList.java:324)
at com.sun.javafx.collections.ObservableListWrapper.get(ObservableListWrapper.java:141)
at com.sun.javafx.scene.control.skin.TextAreaSkin$ContentView.layoutChildren(TextAreaSkin.java:182)
at javafx.scene.Parent.layout(Parent.java:886)
at javafx.scene.Parent.layout(Parent.java:896)
at javafx.scene.Scene.layoutDirtyRoots(Scene.java:428)
at javafx.scene.Scene.doLayoutPass(Scene.java:401)
at javafx.scene.Scene.access$2800(Scene.java:126)
at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:1719)
at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:283)
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:662)

java.lang.IndexOutOfBoundsException
at javafx.scene.control.TextInputControl.replaceText(TextInputControl.java:466)
at com.sun.javafx.scene.control.skin.TextInputControlSkin.handleKeyTypedEvent(TextInputControlSkin.java:567)
at com.sun.javafx.scene.control.skin.TextInputControlSkin$8.handle(TextInputControlSkin.java:114)
at com.sun.javafx.scene.control.skin.TextInputControlSkin$8.handle(TextInputControlSkin.java:111)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:56)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:162)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:115)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:47)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:33)
at javafx.event.Event.fireEvent(Event.java:171)
at javafx.scene.Scene$KeyHandler.process(Scene.java:2821)
at javafx.scene.Scene$KeyHandler.access$1500(Scene.java:2751)
at javafx.scene.Scene.impl_processKeyEvent(Scene.java:1353)
at javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:1784)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:105)
at com.sun.glass.ui.View.handleKeyEvent(View.java:248)
at com.sun.glass.ui.View.notifyKey(View.java:534)
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:662)