Bug 203709 NullPointerException in TableAreaLayout
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/layout/pdf/cache/TableAreaLayout.java
&& cell.getChildrenCount( ) > 0 )
			{
				return false;
			}
		}
		return true;
	}
	private boolean isDropCell( CellArea cell )
	{
		return cell != null && cell.getRowSpan( ) < 0;
	}
	
	protected void mergeDropCell(RowArea row)
	{
		if(unresolvedRow==null )
		{
			return;
		}
		CellArea[] cells = new CellArea[endCol-startCol+1];
		Iterator iter = row.getChildren( );
		while(iter.hasNext( ))
		{
			CellArea cell = (CellArea)iter.next( );
			int colId = cell.getColumnID( );
			
			if(colId>=startCol && colId<=endCol)
			{
				cells[colId-startCol] = cell;
			}
		}