java.lang.IllegalArgumentException: Window must not be zero
   at sun.awt.X11.WindowPropertyGetter.<init>(WindowPropertyGetter.java:56)
   at sun.awt.X11.WindowPropertyGetter.<init>(WindowPropertyGetter.java:73)
   at sun.awt.X11.XlibUtil.isToplevelWindow(XlibUtil.java:304)
   at sun.awt.X11.XWindowPeer.setToplevelTransientFor(XWindowPeer.java:1639)
   at sun.awt.X11.XWindowPeer.addToTransientFors(XWindowPeer.java:1772)
   at sun.awt.X11.XWindowPeer.setModalBlocked(XWindowPeer.java:1579)
   at sun.awt.X11.XWindowPeer.setModalBlocked(XWindowPeer.java:1562)
   at java.awt.Window.setModalBlocked(Window.java:1512)
   at java.awt.Dialog.blockWindow(Dialog.java:1559)
   at java.awt.Dialog.checkShouldBeBlocked(Dialog.java:1603)
   at java.awt.Window.show(Window.java:1041)
   at javax.swing.Popup$HeavyWeightWindow.show(Popup.java:258)
   at javax.swing.Popup.show(Popup.java:107)
   at org.netbeans.modules.editor.hints.HintsUI.showPopup(HintsUI.java:503)
   at org.netbeans.modules.editor.hints.HintsUI.invokeDefaultAction(HintsUI.java:707)
   at org.netbeans.modules.editor.hints.HintsUI.keyPressed(HintsUI.java:747)
   at java.awt.AWTEventMulticaster.keyPressed(AWTEventMulticaster.java:250)
   at java.awt.AWTEventMulticaster.keyPressed(AWTEventMulticaster.java:249)
   at java.awt.Component.processKeyEvent(Component.java:6483)
   at javax.swing.JComponent.processKeyEvent(JComponent.java:2830)
   at java.awt.Component.processEvent(Component.java:6302)
   at java.awt.Container.processEvent(Container.java:2234)
   at java.awt.Component.dispatchEventImpl(Component.java:4881)
   at java.awt.Container.dispatchEventImpl(Container.java:2292)
   at java.awt.Component.dispatchEvent(Component.java:4703)
   at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1954)
   at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:806)
   at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:1074)
   at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:945)
   at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:771)
   at java.awt.Component.dispatchEventImpl(Component.java:4752)
   at java.awt.Container.dispatchEventImpl(Container.java:2292)
   at java.awt.Window.dispatchEventImpl(Window.java:2739)
   at java.awt.Component.dispatchEvent(Component.java:4703)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:751)
   at java.awt.EventQueue.access$500(EventQueue.java:97)
   at java.awt.EventQueue$3.run(EventQueue.java:702)
   at java.awt.EventQueue$3.run(EventQueue.java:696)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86)
   at java.awt.EventQueue$4.run(EventQueue.java:724)
   at java.awt.EventQueue$4.run(EventQueue.java:722)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:721)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)