Bug 93400 LTK UI should provide official API for structural content in the preview page
org.eclipse.ltk.ui.refactoring/src/org/eclipse/ltk/internal/ui/refactoring/PreviewWizardPage.java
}
			private boolean isChild(ChangeElement element, ChangeElement child) {
				while (child != null) {
					if (child == element)
						return true;
					child= child.getParent();
				}
				return false;
			}
		};
	}
		
	private ISelectionChangedListener createSelectionChangedListener() {
		return new ISelectionChangedListener(){
			public void selectionChanged(SelectionChangedEvent event) {
				IStructuredSelection sel= (IStructuredSelection) event.getSelection();
				if (sel.size() == 1) {
					ChangeElement newSelection= (ChangeElement)sel.getFirstElement();
					if (newSelection != fCurrentSelection) {
						fCurrentSelection= newSelection;
						showPreview(newSelection);
					}
				} else {
					showPreview(null);
				}
			}
		};
	}	
	private void showPreview(ChangeElement element) {
		try {