Nifty GUI editor crashes on launch

Nifty GUI editor crashes on launch. Apparently it is missing some dependencies:
java.lang.IllegalStateException: Cannot instantiate com.jme3.gde.gui.view.NiftyGuiVisualElement at org.netbeans.core.spi.multiview.MultiViewFactory$MapMVD.createElement(MultiViewFactory.java:464) at org.netbeans.core.multiview.MultiViewModel.getElementForDescription(MultiViewModel.java:222) at org.netbeans.core.multiview.MultiViewModel.getActiveElement(MultiViewModel.java:132) at org.netbeans.core.multiview.MultiViewModel.getActiveElement(MultiViewModel.java:128) at org.netbeans.core.multiview.MultiViewPeer.showCurrentElement(MultiViewPeer.java:470) at org.netbeans.core.multiview.MultiViewPeer.showCurrentElement(MultiViewPeer.java:462) at org.netbeans.core.multiview.MultiViewPeer$SelectionListener.selectionChanged(MultiViewPeer.java:929) at org.netbeans.core.multiview.MultiViewModel.fireSelectionChanged(MultiViewModel.java:259) at org.netbeans.core.multiview.MultiViewModel.setActiveDescription(MultiViewModel.java:120) at org.netbeans.core.multiview.MultiViewModel$BtnGroup.setSelected(MultiViewModel.java:322) at javax.swing.JToggleButton$ToggleButtonModel.setSelected(JToggleButton.java:254) at javax.swing.ButtonGroup.setSelected(ButtonGroup.java:165) at org.netbeans.core.multiview.MultiViewModel$BtnGroup.setSelected(MultiViewModel.java:318) at org.netbeans.core.multiview.TabsComponent$ButtonMouseListener.mousePressed(TabsComponent.java:907) at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:280) at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:279) at java.awt.Component.processMouseEvent(Component.java:6536) at javax.swing.JComponent.processMouseEvent(JComponent.java:3324) at java.awt.Component.processEvent(Component.java:6304) at java.awt.Container.processEvent(Container.java:2239) at java.awt.Component.dispatchEventImpl(Component.java:4889) at java.awt.Container.dispatchEventImpl(Container.java:2297) at java.awt.Component.dispatchEvent(Component.java:4711) at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4904) at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4532) at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4476) at java.awt.Container.dispatchEventImpl(Container.java:2283) at java.awt.Window.dispatchEventImpl(Window.java:2746) at java.awt.Component.dispatchEvent(Component.java:4711) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:760) at java.awt.EventQueue.access$500(EventQueue.java:97) at java.awt.EventQueue$3.run(EventQueue.java:709) at java.awt.EventQueue$3.run(EventQueue.java:703) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74) at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:84) at java.awt.EventQueue$4.run(EventQueue.java:733) at java.awt.EventQueue$4.run(EventQueue.java:731) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74) at java.awt.EventQueue.dispatchEvent(EventQueue.java:730) at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205) 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) Caused by: java.lang.NoSuchMethodException: com.jme3.gde.gui.view.NiftyGuiVisualElement.() at java.lang.Class.getConstructor0(Class.java:3082) at java.lang.Class.getConstructor(Class.java:1825) at org.netbeans.core.spi.multiview.MultiViewFactory$MapMVD.createElement(MultiViewFactory.java:450) … 47 more Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:423) at org.netbeans.core.spi.multiview.MultiViewFactory$MapMVD.createElement(MultiViewFactory.java:447) … 47 more Caused by: java.lang.NoSuchMethodError: de.lessvoid.nifty.builder.PopupBuilder.childLayoutAbsolute()V at jada.ngeditor.model.utils.NiftyDDManager.(NiftyDDManager.java:32) at jada.ngeditor.guiviews.J2DNiftyView.init(J2DNiftyView.java:154) at com.jme3.gde.gui.view.NiftyGuiVisualElement.(NiftyGuiVisualElement.java:123) … 52 more

Here is the forum post about it:
https://hub.jmonkeyengine.org/t/sdk-vehicle-editing-direct-flash-back-problem/43258/4

The newest Nifty that works with the editor is Nifty 1.4.1 (some rendering code changed after that), current version uses some preview version of Nifty. Also one problem is that our plugin seems to be actually some fork of the official editor (https://github.com/relu91/niftyeditor). And this fork I suspect is only on @normen 's computer somewhere. If that were to be found, we could update it to the latest editor version and Nifty 1.4.1. Host that code somewhere and have the integration work as it used to.

Other way is probably just to try to find out the missing library. Shouldn't also be that hard. I'm talking about the update to latest editor since there are some problems with the editor (source: numerous forum posts), maybe an update would help...?

Start by reproducing the launch failure and reading jada.ngeditor.model.utils.NiftyDDManager.java, jada.ngeditor.guiviews.J2DNiftyView.java, and com.jme3.gde.gui.view.NiftyGuiVisualElement.java around the reported constructor and Nifty API call. Compare the bundled Nifty version with 1.4.1 and investigate the relu91/niftyeditor fork; done means the Nifty GUI editor opens without the NoSuchMethodError and its integration is hosted and maintainable.