Bug 203709 NullPointerException in TableAreaLayout
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/layout/pdf/cache/TableAreaLayout.java
if (cell.getHeight()<0)
					{
							
						CellArea ref = ((DummyCell)cell).getCell( );
						if(!dropCells.contains( ref ))
						{
							ref.setHeight( ref.getHeight( ) - remainCellHeight );
							cell.setHeight( 0 );
							verticalAlign( ref );
							dropCells.add( ref );
						}
					}
					cell.setRowSpan( 1 );
				}
			}
			else if( (cell.getRowSpan() == 1) )
			{
				if ( delta != 0 )
				{
					cell.setHeight( height );
					row.getArea().setHeight(height);
					verticalAlign( cell );	
				}
			}
		}
		
		return delta;	
	}
	
	/*protected void keepUnresolvedCell(Row lastRow)