Bug 200316 [CommonNavigator] Can not contribute property page to classpath container in project explorer
bundles/org.eclipse.ui.navigator.resources/src/org/eclipse/ui/internal/navigator/resources/actions/PropertiesActionProvider.java
IStructuredSelection sSel = (IStructuredSelection) delegate
						.getSelection();
				if (sSel.getFirstElement() instanceof IAdaptable) {
					return sSel;
				}
				return new StructuredSelection(new DelegateIAdaptable(sSel
						.getFirstElement()));
			}
			return delegate.getSelection();
		}
		/*
		 * (non-Javadoc)
		 * 
		 * @see org.eclipse.jface.viewers.ISelectionProvider#removeSelectionChangedListener(org.eclipse.jface.viewers.ISelectionChangedListener)
		 */
		public void removeSelectionChangedListener(
				ISelectionChangedListener listener) {
			delegate.removeSelectionChangedListener(listener);
		}
		/*
		 * (non-Javadoc)
		 * 
		 * @see org.eclipse.jface.viewers.ISelectionProvider#setSelection(org.eclipse.jface.viewers.ISelection)
		 */
		public void setSelection(ISelection selection) {
			delegate.setSelection(selection);
		}
	}
}