java.lang.NullPointerException
   at java.awt.Dialog.conditionalShow(Dialog.java:936)
   at java.awt.Dialog.show(Dialog.java:1030)
   at org.netbeans.core.windows.services.NbPresenter.superShow(NbPresenter.java:1038)
   at org.netbeans.core.windows.services.NbPresenter.doShow(NbPresenter.java:1072)
   at org.netbeans.core.windows.services.NbPresenter.show(NbPresenter.java:1048)
   at java.awt.Component.show(Component.java:1629)
   at java.awt.Component.setVisible(Component.java:1581)
   at java.awt.Window.setVisible(Window.java:977)
   at java.awt.Dialog.setVisible(Dialog.java:1003)
   at org.netbeans.core.windows.services.DialogDisplayerImpl$1AWTQuery.showDialog(DialogDisplayerImpl.java:245)
   at org.netbeans.core.windows.services.DialogDisplayerImpl.notify(DialogDisplayerImpl.java:261)
   at org.netbeans.core.windows.services.DialogDisplayerImpl.notify(DialogDisplayerImpl.java:158)
   at org.netbeans.modules.maven.ActionProviderImpl$ShowProblemsAction.actionPerformed(ActionProviderImpl.java:621)
   at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
   at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
   at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
   at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
   at javax.swing.AbstractButton.doClick(AbstractButton.java:376)
   at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:833)
   at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:877)
   at java.awt.Component.processMouseEvent(Component.java:6437)
   at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
   at java.awt.Component.processEvent(Component.java:6202)
   at java.awt.Container.processEvent(Container.java:2213)
   at java.awt.Component.dispatchEventImpl(Component.java:4793)
   at java.awt.Container.dispatchEventImpl(Container.java:2271)
   at java.awt.Component.dispatchEvent(Component.java:4619)
   at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4816)
   at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4476)
   at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4406)
   at java.awt.Container.dispatchEventImpl(Container.java:2257)
   at java.awt.Window.dispatchEventImpl(Window.java:2677)
   at java.awt.Component.dispatchEvent(Component.java:4619)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:662)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:148)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)