Cant extract subscene because of error of reference

[Aztec2012]

Cant extract subscene because of error of reference.

[AdrienTD]

It's not a bug, you are using it wrong.
Generally you want to extract small pieces of a scene (for example: a door, a plant, ...) so that you can import it to another scene.
Extracting the entire root of a scene, as you did in the screenshot, does not make sense.
Also this is a feature I am still working on, and that I haven't documented yet, please wait until I finish and document it before reporting other issues on that feature.