Bug 178519 Problems in multi-rows header
Please see the attachments.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/layout/pdf/PDFRowLM.java
else
		{
			Iterator iter = root.getChildren( );
			while ( iter.hasNext( ) )
			{
				CellArea cell = (CellArea) iter.next( );
				if ( cell.getChildrenCount( ) > 0 )
				{
					return false;
				}
			}
			if ( this.isRowFinished( ) )
			{
				return false;
			}
			return true;
		}
	}
	public void submit( AbstractArea area )
	{
		CellArea cArea = (CellArea) area;
		root.addChild( area );
		cArea.setPosition( tbl.getXPos( cArea.getColumnID( ) ), 0 );
	}
	protected boolean clearCache( )
	{
		
		return false;
	}
}