NullPointerException - when right clicking on element in ruleset editor tree

NullPointerException when right clicking on element in Ruleset Editor tree. The exception is thrown during the process of computing and creating the context menu

https://paste2.org/AVmX51GV

Discovered while testing with mrizzi@redhat.com

—

java.lang.NullPointerException
at org.eclipse.wst.xml.core.internal.contentmodel.modelqueryimpl.ModelQueryImpl$AvailableContentCMVisitor.computeAvailableContent(ModelQueryImpl.java:649)
at org.eclipse.wst.xml.core.internal.contentmodel.modelqueryimpl.ModelQueryImpl.getAvailableContent(ModelQueryImpl.java:309)
at org.eclipse.wst.xml.core.internal.contentmodel.modelqueryimpl.ModelQueryActionHelper.getInsertChildNodeActions(ModelQueryActionHelper.java:217)
at org.eclipse.wst.xml.core.internal.contentmodel.modelqueryimpl.ModelQueryActionHelper.getInsertActions(ModelQueryActionHelper.java:138)
at org.eclipse.wst.xml.core.internal.contentmodel.modelqueryimpl.ModelQueryImpl.getInsertActions(ModelQueryImpl.java:537)
at org.jboss.tools.windup.ui.internal.rules.delegate.ElementUiDelegate.fillContextMenu(ElementUiDelegate.java:118)
at org.jboss.tools.windup.ui.internal.editor.RulesetEditorRulesSection.fillContextMenu(RulesetEditorRulesSection.java:368)
at org.jboss.tools.windup.ui.internal.editor.RulesetEditorRulesSection.access$2(RulesetEditorRulesSection.java:360)
at org.jboss.tools.windup.ui.internal.editor.RulesetEditorRulesSection$5.menuAboutToShow(RulesetEditorRulesSection.java:349)
at org.eclipse.jface.action.MenuManager.fireAboutToShow(MenuManager.java:339)
at org.eclipse.jface.action.MenuManager.handleAboutToShow(MenuManager.java:470)
at org.eclipse.jface.action.MenuManager.access$1(MenuManager.java:465)
at org.eclipse.jface.action.MenuManager$2.menuShown(MenuManager.java:497)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:256)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:86)
at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5348)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1348)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1374)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1353)
at org.eclipse.swt.widgets.Menu._setVisible(Menu.java:198)
at org.eclipse.swt.widgets.Display.runPopups(Display.java:4644)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:4173)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1150)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1039)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:153)
at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:680)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:594)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:148)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:151)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:388)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:243)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:653)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:590)
at org.eclipse.equinox.launcher.Main.run(Main.java:1499)
at org.eclipse.equinox.launcher.Main.main(Main.java:1472)