java.lang.IllegalArgumentException: null not supported
   at org.netbeans.api.java.source.ui.ElementOpen.open(ElementOpen.java:121)
   at org.netbeans.modules.java.navigation.actions.OpenAction.actionPerformed(OpenAction.java:94)
   at org.openide.explorer.view.TreeView.performPreferredActionOnNodes(TreeView.java:1671)
   at org.openide.explorer.view.TreeView$PopupSupport.actionPerformed(TreeView.java:1651)
   at javax.swing.JComponent$ActionStandin.actionPerformed(JComponent.java:3422)
   at javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1661)
   at javax.swing.JComponent.processKeyBinding(JComponent.java:2879)
   at javax.swing.JComponent.processKeyBindings(JComponent.java:2926)
   at javax.swing.JComponent.processKeyEvent(JComponent.java:2842)
   at java.awt.Component.processEvent(Component.java:6281)
   at java.awt.Container.processEvent(Container.java:2229)
   at java.awt.Component.dispatchEventImpl(Component.java:4860)
   at java.awt.Container.dispatchEventImpl(Container.java:2287)
   at java.awt.Component.dispatchEvent(Component.java:4686)
   at org.openide.explorer.view.TreeView$ExplorerTree$SearchFieldListener.keyPressed(TreeView.java:2340)
   at java.awt.Component.processKeyEvent(Component.java:6462)
   at javax.swing.JComponent.processKeyEvent(JComponent.java:2829)
   at org.openide.explorer.view.TreeView$8.processKeyEvent(TreeView.java:1731)
   at java.awt.Component.processEvent(Component.java:6281)
   at java.awt.Container.processEvent(Container.java:2229)
   at java.awt.Component.dispatchEventImpl(Component.java:4860)
   at java.awt.Container.dispatchEventImpl(Container.java:2287)
   at java.awt.Component.dispatchEvent(Component.java:4686)
   at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1908)
   at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:752)
   at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:1017)
   at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:889)
   at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:717)
   at java.awt.Component.dispatchEventImpl(Component.java:4730)
   at java.awt.Container.dispatchEventImpl(Container.java:2287)
   at java.awt.Window.dispatchEventImpl(Window.java:2713)
   at java.awt.Component.dispatchEvent(Component.java:4686)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
   at java.awt.EventQueue.access$000(EventQueue.java:101)
   at java.awt.EventQueue$3.run(EventQueue.java:666)
   at java.awt.EventQueue$3.run(EventQueue.java:664)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
   at java.awt.EventQueue$4.run(EventQueue.java:680)
   at java.awt.EventQueue$4.run(EventQueue.java:678)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:153)
   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)