Added check for container class for prop to be added

Patch provided:

alexandru.dumitru → made their first commit to this issue’s fork.

This is very hard for anyone to understand why you need this. Could you provide more info on where it is failing and why you need to add the container?

Also the status "Patch (to be ported)" is not correct in my eyes. So moving to needs work to provide more info on steps to reproduce.