java.lang.IllegalStateException: The model is not initialized or is broken.
   at org.netbeans.modules.xml.xdm.XDMModel.checkStableOrParsingState(XDMModel.java:980)
   at org.netbeans.modules.xml.xdm.XDMModel.mutate(XDMModel.java:343)
   at org.netbeans.modules.xml.xdm.XDMModel.mutate(XDMModel.java:339)
   at org.netbeans.modules.xml.xdm.XDMModel.append(XDMModel.java:615)
   at org.netbeans.modules.xml.xdm.xam.XDMAccess.appendChild(XDMAccess.java:267)
   at org.netbeans.modules.xml.xam.dom.AbstractDocumentComponent.appendChildQuietly(AbstractDocumentComponent.java:296)
   at org.netbeans.modules.xml.xam.dom.AbstractDocumentComponent.appendChildQuietly(AbstractDocumentComponent.java:75)
   at org.netbeans.modules.xml.xam.AbstractComponent._appendChildQuietly(AbstractComponent.java:113)
   at org.netbeans.modules.xml.xam.AbstractComponent.addChild(AbstractComponent.java:302)
   at org.netbeans.modules.xml.xam.AbstractComponent.setChild(AbstractComponent.java:435)
   at org.netbeans.modules.xml.xam.AbstractComponent.setChildAfter(AbstractComponent.java:413)
   at org.netbeans.modules.xml.xam.AbstractComponent.setChild(AbstractComponent.java:408)
   at org.netbeans.modules.maven.model.pom.impl.ProjectImpl.addDependency(ProjectImpl.java:360)
   at org.netbeans.modules.maven.api.ModelUtils.checkModelDependency(ModelUtils.java:121)
   at org.netbeans.modules.maven.api.ModelUtils$1.performOperation(ModelUtils.java:89)
   at org.netbeans.modules.maven.api.ModelUtils$1.performOperation(ModelUtils.java:87)
   at org.netbeans.modules.maven.model.Utilities.performPOMModelOperations(Utilities.java:319)
   at org.netbeans.modules.maven.api.ModelUtils.addDependency(ModelUtils.java:103)
   at org.netbeans.modules.maven.nodes.DependenciesNode$AddDependencyAction.actionPerformed(DependenciesNode.java:361)
   at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
   at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
   at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
   at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
   at javax.swing.AbstractButton.doClick(AbstractButton.java:357)
   at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1225)
   at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1266)
   at java.awt.Component.processMouseEvent(Component.java:6263)
   at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
   at java.awt.Component.processEvent(Component.java:6028)
   at java.awt.Container.processEvent(Container.java:2041)
   at java.awt.Component.dispatchEventImpl(Component.java:4630)
   at java.awt.Container.dispatchEventImpl(Container.java:2099)
   at java.awt.Component.dispatchEvent(Component.java:4460)
   at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4574)
   at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4238)
   at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4168)
   at java.awt.Container.dispatchEventImpl(Container.java:2085)
   at java.awt.Window.dispatchEventImpl(Window.java:2475)
   at java.awt.Component.dispatchEvent(Component.java:4460)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)