Bug 176450 Support link to CSS Feature(Model Part)
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/util/ModelUtil.java
Object item = list.get( i );
			if ( item instanceof IStructure )
			{
				returnList.add( ( (IStructure) item ).copy( ) );
			}
			else
			{
				assert false;
			}
		}
		return returnList;
	}
	/**
	 * Clones the value.
	 * <ul>
	 * <li>If the value is of simple type, like integer, or string, the
	 * original value will be returned.
	 * <li>If the value is strcuture list, the cloned structure list will be
	 * cloned.
	 * <li>If the value is structure, the cloned structure will be cloned.
	 * <li>If the value is element/strucuture reference value, the
	 * element/structure name will be returned.
	 * </ul>
	 * 
	 * @param propDefn
	 *            definition of property
	 * @param value
	 *            value to clone
	 * @return new value
	 */