Bug 213981 [Automation] [Regression] Exception is thrown out when preview the attached report design [07]
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/internal/document/v4/ExtendedItemExecutor.java
else
				{
					InstanceIndex leftIndex = (InstanceIndex) leftEdge;
					InstanceID leftId = leftIndex.getInstanceID( );
					nextOffset = leftIndex.getOffset( );
					uniqueId = leftId.getUniqueID( );
				}
			}
		}
		
		
		if ( nextOffset == -1 )
		{
			return null;
		}
		ReportItemExecutor childExecutor = doCreateExecutor( nextOffset );
		if ( childExecutor != null )
		{
			IContent childContent = childExecutor.execute( );
			if ( childContent != null )
			{
				
				if ( fragment != null )
				{
					InstanceID childId = childContent.getInstanceID( );
					Fragment childFragment = fragment.getFragment( childId );
					if ( childFragment != null )
					{
						childExecutor.setFragment( childFragment );
					}