java.lang.NullPointerException
        at org.netbeans.modules.editor.hints.AnnotationHolder.removeUpdate(AnnotationHolder.java:410)
        at org.netbeans.lib.editor.util.swing.PriorityDocumentListenerList.removeUpdate(PriorityDocumentListenerList.java:99)
        at javax.swing.text.AbstractDocument.fireRemoveUpdate(AbstractDocument.java:243)
        at org.netbeans.editor.BaseDocument.fireRemoveUpdate(BaseDocument.java:1626)
        at org.netbeans.editor.BaseDocument.remove(BaseDocument.java:925)
        at org.netbeans.modules.editor.guards.PositionBounds$1.run(PositionBounds.java:212)
        at org.netbeans.editor.GuardedDocument.runAtomic(GuardedDocument.java:324)
        at org.openide.text.NbDocument.runAtomic(NbDocument.java:411)
        at org.netbeans.modules.editor.guards.PositionBounds.setText(PositionBounds.java:245)
        at org.netbeans.modules.editor.guards.GuardedSectionImpl.setText(GuardedSectionImpl.java:178)
        at org.netbeans.modules.editor.guards.SimpleSectionImpl.setText(SimpleSectionImpl.java:73)
        at org.netbeans.api.editor.guards.SimpleSection.setText(SimpleSection.java:66)
        at org.netbeans.modules.form.JavaCodeGenerator.regenerateVariables(JavaCodeGenerator.java:1186)
        at org.netbeans.modules.form.JavaCodeGenerator.regenerateCode(JavaCodeGenerator.java:3469)
        at org.netbeans.modules.form.FormEditorSupport$JavaEditorTopComponent.componentShowing(FormEditorSupport.java:1250)
        at org.netbeans.core.multiview.MultiViewPeer.showCurrentElement(MultiViewPeer.java:295)
        at org.netbeans.core.multiview.MultiViewPeer.showCurrentElement(MultiViewPeer.java:265)
        at org.netbeans.core.multiview.MultiViewPeer$SelectionListener.selectionChanged(MultiViewPeer.java:673)
        at org.netbeans.core.multiview.MultiViewModel.fireSelectionChanged(MultiViewModel.java:243)
        at org.netbeans.core.multiview.MultiViewModel.setActiveDescription(MultiViewModel.java:115)
        at org.netbeans.core.multiview.MultiViewModel$BtnGroup.setSelected(MultiViewModel.java:293)
        at javax.swing.JToggleButton$ToggleButtonModel.setSelected(JToggleButton.java:237)
        at javax.swing.ButtonGroup.setSelected(ButtonGroup.java:147)
        at org.netbeans.core.multiview.MultiViewModel$BtnGroup.setSelected(MultiViewModel.java:289)
        at org.netbeans.core.multiview.TabsComponent$ButtonMouseListener.mousePressed(TabsComponent.java:444)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:263)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:262)
        at java.awt.Component.processMouseEvent(Component.java:6038)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3265)
        at java.awt.Component.processEvent(Component.java:5806)
        at java.awt.Container.processEvent(Container.java:2058)
        at java.awt.Component.dispatchEventImpl(Component.java:4413)
        at java.awt.Container.dispatchEventImpl(Container.java:2116)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4322)
        at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:3983)
        at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:3916)
        at java.awt.Container.dispatchEventImpl(Container.java:2102)
        at java.awt.Window.dispatchEventImpl(Window.java:2440)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:117)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)