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/SimpleGroupElementHandle.java
if ( isPropertyVisible( propDefn.getName( ) ) )
			{
				visibleList.add( propDefn );
			}
		}
		return new GroupPropertyIterator( visibleList );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.api.GroupElementHandle#isPropertyVisible(java.lang.String)
	 */
	protected boolean isPropertyVisible( String propName )
	{
		List elements = getElements( );
		for ( int i = 0; i < elements.size( ); i++ )
		{
			PropertyHandle propertyHandle = ( (DesignElementHandle) elements
					.get( i ) ).getPropertyHandle( propName );
			
			
			
			if ( propertyHandle != null && !propertyHandle.isVisible( )
					|| propertyHandle == null )
				return false;
		}
		
		
		return !needHide( propName );
	}