-t/--top-level ignored when using directory input

Hello,
I have a folder containing many types, each one in its folder, like in the "Multiple JSON" example here https://app.quicktype.io/

The JSON Schema generated has only "definitions" but no top-level type.

I would like to set the top level type using the -t/--top-level option but it seems ignored.

Is it the attended behaviour?

When I use the -t/--top-level option with files input, it works as expected.

Thank you.