We extended the possibility to show a label for the container form control in the latest dhx.Suite update (v7.3).
You can check it in the following snippets:
https://snippet.dhtmlx.com/ikyyekxq
https://snippet.dhtmlx.com/cnxi9eqq
Please, download the latest available dhx.Suite build to get this functionality.
Thank you for your report.
Best regards.