[bug] Not being able to apply self-defined css classes to Layout Container

[cthio]

Describe the bug
Layout Container not able to register the custom CSS classes defined in the Template Policy. I'm running a React SPA pages in AEM

Package version
v1.1.10 with AEM 6.5.5

To Reproduce

1. Go to any SPA Page template
2. In an existing Layout Container component, go to its template policy
3. Add the custom css class and go back to the template editor page
4. Hover the layout container and add the css class with the Styles icon
5. CSS classes are not being applied to the Layout Container

Expected behavior
The CSS class(es) should be applied to the Layout Container

Screenshots
1.

3. Actual behavior
   

Additional context
Add any other context about the problem here.

[friendlymahi]

@schoudry - Should your fix resolve this issue? Thanks

[schoudry]

are the custom classes returned in model.json request in appliedCssClassNames property?

[camillalund]

We have the same problem. None of the properties from the container policy are returned in model.json

[friendlymahi]

@camillalund @cthio - Unsure if this issue should even exist under this repo. If the model.json doesnt even return the appliedCssClassNames property, perhaps the issue is with the sling model exporters from core components, and it may make sense to log the issue in https://github.com/adobe/aem-core-wcm-components.

[gabrielwalt]

See comment on adobe/aem-core-wcm-components#1889:
Please open a support ticket for us to back-port this to 6.5.
Thanks!