We are unable to add new JRXML inside the report unit.
Release : 16.1.2
In JSS 7.1, there is an option to add JRXML inside the report unit. When we compare this behavior with JSS 7.9, there is no option available to add the report unit.
The option is available again in JRS 8.0.2
https://community.jaspersoft.com/wiki/subreports-jaspersoft-studio