Bug 146481 Name is not necessary for extended element
Steps to reproduce: 1.New a label named "label" in library 2.New a report, extend lib.label Expected result: No name for the extended label Actual result: "label" is added as the name of label in report. It's not reasonable because "Restore Properties" is enabled even without properties change.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/GroupElementHandle.java
*         <code>DesignElementHandle</code>.
	 */
	abstract public boolean isSameType( );
	/**
	 * Returns the common properties shared by the given group of
	 * elements(including user properties). Contents of the list is element
	 * property definitions. If elements do not share any common property,
	 * return an empty list.
	 * 
	 * @return the common properties shared by the given group of elements. If
	 *         elements do not share any common property, or the given list is
	 *         empty, or the list contains any item that is not an instance of
	 *         <code>DesignElementHandle</code>, return an empty list.
	 */
	abstract public List getCommonProperties( );
	/**
	 * Returns an iterator over the common properties. Contents of the iterator
	 * are handles to the common properties, type of them is
	 * <code>GroupPropertyHandle</code>. Note: remove is not support for the
	 * iterator.
	 * 
	 * @return an iterator over the common properties. Contents of the iterator
	 *         are handles to the common properties, type of them is
	 *         <code>GroupPropertyHandle</code>
	 */
	public final Iterator propertyIterator( )
	{
		return new GroupPropertyIterator( getCommonProperties( ) );
	}
	/**