If you add a TextBox to a scene and then hover your mouse over the TextBox and rotate the mouse wheel (no click necessary), the following NPE is thrown (source code attached):

java.lang.NullPointerException
at com.sun.javafx.scene.control.behavior.TextBoxBehavior.mouseWheelMove(TextBoxBehavior.java:105)
at com.sun.javafx.scene.control.skin.TextBoxSkin$2.handle(TextBoxSkin.java:65)
at com.sun.javafx.scene.control.skin.TextBoxSkin$2.handle(TextBoxSkin.java:63)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:59)
at com.sun.javafx.event.DefaultEventDispatcher.dispatchBubblingEvent(DefaultEventDispatcher.java:173)
at com.sun.javafx.event.DefaultEventDispatcher.dispatchBubblingEvent(DefaultEventDispatcher.java:157)
at com.sun.javafx.event.DefaultEventDispatcher.dispatchEvent(DefaultEventDispatcher.java:120)
at javafx.scene.Node$28.dispatchEvent(Node.java:5069)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.DefaultEventDispatcher.dispatchEvent(DefaultEventDispatcher.java:118)
at javafx.scene.Node$28.dispatchEvent(Node.java:5069)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.DefaultEventDispatcher.dispatchEvent(DefaultEventDispatcher.java:118)
at javafx.scene.Node$28.dispatchEvent(Node.java:5069)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.DefaultEventDispatcher.dispatchEvent(DefaultEventDispatcher.java:118)
at javafx.scene.Node$28.dispatchEvent(Node.java:5069)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.DefaultEventDispatcher.dispatchEvent(DefaultEventDispatcher.java:118)
at javafx.scene.Node$28.dispatchEvent(Node.java:5069)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.DefaultEventDispatcher.dispatchEvent(DefaultEventDispatcher.java:118)
at javafx.scene.Node$28.dispatchEvent(Node.java:5069)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.DefaultEventDispatcher.dispatchEvent(DefaultEventDispatcher.java:118)
at javafx.scene.Node$28.dispatchEvent(Node.java:5069)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.EventRedirector.dispatchEvent(EventRedirector.java:93)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at javafx.event.Event.fireEventImpl(Event.java:172)
at javafx.event.Event.fireEvent(Event.java:162)
at javafx.scene.Node.fireEvent(Node.java:5174)
at javafx.scene.Scene$MouseHandler.process(Scene.java:2096)
at javafx.scene.Scene$MouseHandler.process(Scene.java:1931)
at javafx.scene.Scene$MouseHandler.access$1000(Scene.java:1903)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1020)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:1548)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:122)
at com.sun.glass.ui.View.handleMouseEvent(View.java:254)
at com.sun.glass.ui.View.notifyMouse(View.java:511)
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.run(WinApplication.java:51)