Bug 259179 [TabbedProperties] TabbedPropertySheetPage extensibility option
bundles/org.eclipse.ui.views.properties.tabbed/src/org/eclipse/ui/views/properties/tabbed/TabbedPropertySheetPage.java
extends LabelProvider {
		public String getText(Object element) {
			if (element instanceof ITabDescriptor) {
				return ((ITabDescriptor) element).getLabel();
			}
			return null;
		}
	}
	/**
	 * SelectionChangedListener for the ListViewer.
	 */
	class SelectionChangedListener
		implements ISelectionChangedListener {
		/**
		 * Shows the tab associated with the selection.
		 */
		public void selectionChanged(SelectionChangedEvent event) {
			IStructuredSelection selection = (IStructuredSelection) event
				.getSelection();