Problem Description:
NPE is happening while running a JavaFX application on a machine with multiple display devices. Whenever drag application from one display to other it is consistently throwing NPE.

Steps to reproduce:
- Set the display devices as shown in the attachments(display1.png and display2.png).
- Run the attached javafx application - SwingFx.java(or any simple javafx application)
- Drag the javafx window from one display to other, while dragging keep mouse pointer 1/3 of the title bar on dragging side.

It is related to bug JDK-8185890(it was intermittent in linux platform), but this bug is consistent in Windows 10.

Stacktrace:
Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
              at sun.swing.JLightweightFrame.updateClientCursor(JLightweightFrame.java:473)
              at sun.swing.JLightweightFrame.access$000(JLightweightFrame.java:79)
              at sun.swing.JLightweightFrame$1.updateCursor(JLightweightFrame.java:112)
              at sun.awt.windows.WLightweightFramePeer.updateCursorImmediately(WLightweightFramePeer.java:92)
              at java.awt.Component.updateCursorImmediately(Component.java:3148)
              at java.awt.Container.validate(Container.java:1642)
              at java.awt.Window.dispatchEventImpl(Window.java:2744)
              at java.awt.Component.dispatchEvent(Component.java:4711)
              at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
              at java.awt.EventQueue.access$500(EventQueue.java:97)
              at java.awt.EventQueue$3$1.run(EventQueue.java:714)
              at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
              at java.security.AccessController.doPrivileged(Native Method)
              at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
              at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
              at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
              at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
              at java.lang.Thread.run(Thread.java:748)