Pentaho Report - How to repeat header of multiple subreports

I am creating a report with two tables.

The structure is like this:

-----Page Header of Main Report-----

-----Report Header of Main Report-----

-----Group Header of Sub Report 1-----

-----Details of Sub Report 1------

-----Detail Footer of Sub Report 1------

-----Group Header of Sub Report 2-----

-----Details of Sub Report 2------

-----Detail Footer of Sub Report 2------

-----Report Footer of Main Report-----

-----Page Footer of Main Report-----

This issue is when the details in sub report 1 or 2 is very long, the group header of sub reports cannot repeat in the following pages, even when I have already set "repeat-header" and "sticky" to True in the group header of both main report and the two sub reports.

I have tried to place the sub reports in report header, group header and detail. All fail.

May I know how to repeat the headers of the sub reports when the details of sub reports has multiple pages?

Thank you.

The issue is resolved after:

1. Converting the inline sub reports into banded reports
2. Change the page header and page footer of both main reports and sub reports to sticky.