org.eclipse.core.commands.ExecutionException: While executing the operation, an exception occurred
	at org.eclipse.core.commands.operations.DefaultOperationHistory.execute(DefaultOperationHistory.java:503)
	at org.eclipse.sirius.diagram.ui.tools.internal.editor.DDiagramCommandStack.execute(DDiagramCommandStack.java:73)
	at org.eclipse.sirius.diagram.ui.tools.internal.editor.DDiagramCommandStack.execute(DDiagramCommandStack.java:54)
	at org.eclipse.gmf.runtime.diagram.ui.actions.DiagramAction.execute(DiagramAction.java:141)
	at org.eclipse.gmf.runtime.diagram.ui.actions.DiagramAction.doRun(DiagramAction.java:103)
	at org.eclipse.gmf.runtime.diagram.ui.actions.internal.ArrangeAction.doRun(ArrangeAction.java:278)
	at org.eclipse.gmf.runtime.common.ui.action.AbstractActionHandler.run(AbstractActionHandler.java:359)
	at org.eclipse.gmf.runtime.common.ui.action.ActionManager$1.run(ActionManager.java:225)
	at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:72)
	at org.eclipse.gmf.runtime.common.ui.action.ActionManager.run(ActionManager.java:223)
	at org.eclipse.gmf.runtime.common.ui.action.AbstractActionHandler.runWithEvent(AbstractActionHandler.java:377)
	at org.eclipse.ui.actions.RetargetAction.runWithEvent(RetargetAction.java:225)
	at org.eclipse.gmf.runtime.common.ui.action.ActionMenuManager$MenuCreatorAction.runWithEvent(ActionMenuManager.java:216)
	at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:580)
	at org.eclipse.jface.action.ActionContributionItem.lambda$5(ActionContributionItem.java:451)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4131)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1056)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3944)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3547)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1173)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1062)
	at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:155)
	at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:635)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
	at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:559)
	at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
	at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:155)
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:203)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:137)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:107)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:400)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:255)
	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:660)
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:597)
	at org.eclipse.equinox.launcher.Main.run(Main.java:1468)
	at org.eclipse.equinox.launcher.Main.main(Main.java:1441)
Caused by: java.lang.NullPointerException
	at org.eclipse.gmf.runtime.notation.impl.ViewImpl.getNamedStyle(ViewImpl.java:496)
	at org.eclipse.sirius.diagram.elk.GmfLayoutCommand.doExecuteWithResult(GmfLayoutCommand.java:227)
	at org.eclipse.gmf.runtime.emf.commands.core.command.AbstractTransactionalCommand.doExecute(AbstractTransactionalCommand.java:247)
	at org.eclipse.emf.workspace.AbstractEMFOperation.execute(AbstractEMFOperation.java:150)
	at org.eclipse.gmf.runtime.diagram.ui.commands.ICommandProxy.execute(ICommandProxy.java:68)
	at org.eclipse.gef.commands.CompoundCommand.execute(CompoundCommand.java:129)
	at org.eclipse.gef.commands.CompoundCommand.execute(CompoundCommand.java:129)
	at org.eclipse.gef.commands.CompoundCommand.execute(CompoundCommand.java:129)
	at org.eclipse.gmf.runtime.diagram.ui.commands.CommandProxy.doExecuteWithResult(CommandProxy.java:50)
	at org.eclipse.gmf.runtime.common.core.command.AbstractCommand.execute(AbstractCommand.java:134)
	at org.eclipse.emf.workspace.CompositeEMFOperation.doExecute(CompositeEMFOperation.java:217)
	at org.eclipse.emf.workspace.AbstractEMFOperation.execute(AbstractEMFOperation.java:150)
	at org.eclipse.gmf.runtime.diagram.ui.commands.ArrangeCommand.doExecuteWithResult(ArrangeCommand.java:95)
	at org.eclipse.gmf.runtime.emf.commands.core.command.AbstractTransactionalCommand.doExecute(AbstractTransactionalCommand.java:247)
	at org.eclipse.emf.workspace.AbstractEMFOperation.execute(AbstractEMFOperation.java:150)
	at org.eclipse.gmf.runtime.common.core.command.CompositeCommand.doExecuteWithResult(CompositeCommand.java:403)
	at org.eclipse.gmf.runtime.common.core.command.AbstractCommand.execute(AbstractCommand.java:134)
	at org.eclipse.gmf.runtime.common.core.command.CompositeCommand.doExecuteWithResult(CompositeCommand.java:403)
	at org.eclipse.gmf.runtime.common.core.command.AbstractCommand.execute(AbstractCommand.java:134)
	at org.eclipse.sirius.diagram.ui.tools.internal.commands.WrappingCommandIgnoringAffectedFiles.execute(WrappingCommandIgnoringAffectedFiles.java:125)
	at org.eclipse.core.commands.operations.DefaultOperationHistory.execute(DefaultOperationHistory.java:495)
	... 41 more