Bug 139346 Using isTopN in table inside list group header doesn't work.
Description: Using isTopN in table inside list group header doesn't work. Steps to reproduce: 1.Insert a list with a group 2.Insert a table to list group header 3.Using Total.isTopN(row[],2,null,0) as filter expression in table item. 4.Preview Result: Only the first group displayed top 2 records, other groups kept display all records.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/QueryExecutor.java
IFilterDefinition src = (IFilterDefinition) it.next();
				IBaseExpression expr = src.getExpression();
				if ( isGroupFilter( src )) {
					ConditionalExpression ce = ((ConditionalExpression) expr);
					String exprText = ce.getExpression().getText();
					ColumnInfo columnInfo = QueryExecutorUtil
							.getColInfoFromJSExpr(cx, exprText);
					int index = columnInfo.getColumnIndex();
					String name = columnInfo.getColumnName();
					if (name == null && index < 0) {
						
						
						
						temporaryComputedColumns.add(new ComputedColumn(
								"_{$TEMP_FILTER_" + i + "$}_", exprText,
								DataType.ANY_TYPE));
						it.remove();
						result.add(new FilterDefinition(
								new ConditionalExpression(new ScriptExpression(
										String.valueOf("dataSetRow[\"_{$TEMP_FILTER_" + i
												+ "$}_\"]")), ce.getOperator(), ce
										.getOperand1(), ce.getOperand2())));
					}
				}
			}
		}
	}
	/**
	 * 
	 * @param filter