java.lang.AssertionError: Scene.validate was not called after last change. Widget is not validated. See first Q/A at http://graph.netbeans.org/faq.html page.
   at org.netbeans.api.visual.widget.Widget.paint(Widget.java:1402)
   at org.netbeans.api.visual.widget.Widget.paintChildren(Widget.java:1481)
   at org.netbeans.api.visual.widget.Widget.paint(Widget.java:1427)
   at org.netbeans.api.visual.widget.Widget.paintChildren(Widget.java:1481)
   at org.netbeans.api.visual.widget.Widget.paint(Widget.java:1427)
   at org.netbeans.api.visual.widget.SceneComponent.paint(SceneComponent.java:140)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JViewport.paint(JViewport.java:731)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at org.netbeans.core.windows.view.ui.MultiSplitPane.paint(MultiSplitPane.java:341)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JLayeredPane.paint(JLayeredPane.java:585)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at org.netbeans.core.windows.view.ui.MainWindow$1.paint(MainWindow.java:179)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JLayeredPane.paint(JLayeredPane.java:585)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paintToOffscreen(JComponent.java:5228)
   at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1482)
   at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1413)
   at javax.swing.BufferStrategyPaintManager.paint(BufferStrategyPaintManager.java:311)
   at javax.swing.RepaintManager.paint(RepaintManager.java:1206)
   at javax.swing.JComponent.paint(JComponent.java:1040)
   at java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:39)
   at sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:78)
   at sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:115)
   at java.awt.Container.paint(Container.java:1967)
   at java.awt.Window.paint(Window.java:3877)
   at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:781)
   at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:728)
   at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:677)
   at javax.swing.RepaintManager.access$700(RepaintManager.java:59)
   at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1621)
   at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:721)
   at java.awt.EventQueue.access$200(EventQueue.java:103)
   at java.awt.EventQueue$3.run(EventQueue.java:682)
   at java.awt.EventQueue$3.run(EventQueue.java:680)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:691)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)