"Unhandled event loop exception" after Refresh after second try to open Mapping Diagram with no elements in configuration

1) create 2 console configs, first should has configuration items other without items;
2) open mapping diagram for first press Refresh;
3) open mapping diagram for second press Refresh;
4) close both mapping diagrams;
5) open mapping diagram for second CC, press Refresh -> get exception:
(when exception arise constantly after Refresh)

java.lang.IllegalArgumentException: Argument cannot be null
at org.eclipse.swt.SWT.error(SWT.java:4064)
at org.eclipse.swt.SWT.error(SWT.java:3998)
at org.eclipse.swt.SWT.error(SWT.java:3969)
at org.eclipse.swt.widgets.TreeItem.checkNull(TreeItem.java:207)
at org.eclipse.swt.widgets.TreeItem.<init>(TreeItem.java:197)
at org.eclipse.gef.editparts.AbstractTreeEditPart.addChildVisual(AbstractTreeEditPart.java:75)
at org.eclipse.gef.editparts.AbstractEditPart.addChild(AbstractEditPart.java:210)
at org.eclipse.gef.editparts.AbstractEditPart.refreshChildren(AbstractEditPart.java:771)
at org.eclipse.gef.editparts.AbstractEditPart.refresh(AbstractEditPart.java:718)
at org.eclipse.gef.editparts.AbstractEditPart.addNotify(AbstractEditPart.java:252)
at org.eclipse.gef.editparts.AbstractEditPart.addChild(AbstractEditPart.java:211)
at org.eclipse.gef.editparts.RootTreeEditPart.setContents(RootTreeEditPart.java:140)
at org.eclipse.gef.ui.parts.AbstractEditPartViewer.setContents(AbstractEditPartViewer.java:617)
at org.eclipse.gef.ui.parts.AbstractEditPartViewer.setContents(AbstractEditPartViewer.java:626)
at org.jboss.tools.hibernate.ui.diagram.editors.DiagramContentOutlinePage.setContents(DiagramContentOutlinePage.java:298)
at org.jboss.tools.hibernate.ui.diagram.editors.actions.RefreshAction.run(RefreshAction.java:42)
at org.eclipse.jface.action.Action.runWithEvent(Action.java:498)
at org.eclipse.ui.actions.RetargetAction.runWithEvent(RetargetAction.java:230)
at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:584)
at org.eclipse.jface.action.ActionContributionItem.access$2(ActionContributionItem.java:501)
at org.eclipse.jface.action.ActionContributionItem$6.handleEvent(ActionContributionItem.java:452)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4066)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3657)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2640)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2604)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2438)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:671)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:664)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:115)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:369)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:619)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:574)
at org.eclipse.equinox.launcher.Main.run(Main.java:1407)