CustomGroupBuilder.headerWithSubtotal() doesn't work when exporting to Excel (toXlsx or toXls)

[juan-diego]

When exporting a report to Excel the grouping rows values are not printed when headerWithSubtotal() is set.

This issue can be reproduced with net.sf.dynamicreports.examples.group.GroupHeaderWithSubtotalReport example

Expected Behavior

When exporting to Excel I expect to see the grouping row values as they are printed in the PDF

Current Behavior

However when exporting to Excel (either toXlsx or toXls) the values are missed

Possible Solution

Just as hint... In example GroupHeaderWithSubtotalReport if line 77 is edited by removing .headerWithSubtotal() as follows

CustomGroupBuilder yearGroup = grp.group(new ExportReport.YearExpression()).groupByDataType();

Then the grouping rows values are printed

Steps to Reproduce (for bugs)

This can be reproduced just by replacing line 90 at GroupHeaderWithSubtotalReport

.show();

by

.toXlsx(export.xlsxExporter("export.xlsx"));

Context

This bug makes it no posible to have the grouping rows values printed together with the subtotals in excel files.

Your Environment

• Version used: tested with 6.11.1 and 6.12.1
• Java version being used: openjdk version "11.0.9" 2020-10-20
• Operating System and version (desktop or mobile): macOS Big Sur 11.4