NPE when disposing Outline view in Eclipse

[ripla]

Steps to reproduce

Unknown

Actual behavior

Exception:

java.lang.NullPointerException
	at com.vaadin.designer2.eclipse.views.outline.AbstractOutlineView.dispose(AbstractOutlineView.java:185)
	at com.vaadin.designer2.eclipse.editors.DesignVisualEditor.dispose(DesignVisualEditor.java:424)
	at org.eclipse.ui.part.MultiPageEditorPart$4.run(MultiPageEditorPart.java:1014)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.ui.part.MultiPageEditorPart.disposePart(MultiPageEditorPart.java:1010)
	at org.eclipse.ui.part.MultiPageEditorPart.dispose(MultiPageEditorPart.java:507)
	at com.vaadin.designer2.eclipse.editors.AbstractDesignerEditor.dispose(AbstractDesignerEditor.java:161)
	at com.vaadin.designer2.eclipse.editors.framework.VaadinEditor.dispose(VaadinEditor.java:159)

IDE, Designer and OS version

Eclipse. Unknown Designer version & OS