Bug 120503 Cascading Parameter can not drop into layout
Details: Cascading Parameter can not drop into layout Step: 1.Open a report design and Create a Sample Data Source and data set by "select * from CLASSICMODELS.CUSTOMERS" 2.New a cascading parameter and create CUSTOMERSNUMBER and CUSTOMERSNAME in parameter named number and name. Press OK 3.Drop parameter name into layout. Actual results: The parameter in Cascading Parameter Group can not drop to layout
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
* Gets the element name. The object is a long string that separated with
	 * the separator "."
	 * 
	 * @param obj
	 *            the object
	 * @return the name behind the last separator "."
	 */
	public static String getElementName( Object obj )
	{
		if ( obj instanceof Class )
		{
			obj = ( (Class) obj ).getName( );
		}
		return obj.toString( ).substring(
				obj.toString( ).lastIndexOf( "." ) + 1 ); 
	}
	/**
	 * Gets the definition for the element with the specified name
	 * 
	 * @param elementName
	 *            the name of the element
	 * 
	 * @return Returns the definition, or null if the element is not defined.
	 */
	public static IElementDefn getElementDefn( String elementName )
	{
		IElementDefn defn = DesignEngine.getMetaDataDictionary( ).getElement(
				elementName );
		if ( defn == null )
		{