Bug 145698 Name change won't enable "restore property" button
Steps to reproduce: 1.New a report, extends lib.label 2.Choose the label, switch to property editor, chang its name to "aa" 3.Choose the label again Expected result: "Restore property" button is enabled Actual result: "Restore property" button is grayed out
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/GroupElementHandle.java
* @param propName
	 *            name of the property.
	 * @return <code>true</code> if the group of element share the same value.
	 *         Return <code>false</code> if the property is not a common
	 *         property or elements have different values for this property.
	 */
	public final boolean shareSameValue( String propName )
	{
		GroupPropertyHandle propHandle = getPropertyHandle( propName );
		if ( propHandle == null )
			return false;
		return propHandle.shareSameValue( );
	}
	/**
	 * Set the value of a property on the given collection of elements. If the
	 * property provided is not a common property then this method simply
	 * return; Otherwise, the value will be set on the group of elements.
	 * 
	 * @param propName
	 *            name of the property.
	 * @param value
	 *            value needs to set.
	 * @throws SemanticException
	 *             if the value is invalid for the property, or the property is
	 *             undefined on the elements.
	 * @see GroupPropertyHandle#setValue(Object)
	 */
	public final void setProperty( String propName, Object value )
			throws SemanticException
	{