The selected container node is removed from the graph area of the Hypergraph and deleted from the file. The nodes within the deleted container are either moved to the parent container (if one exists), or to the top level of the dependency graph. Note that all connections (published or unpublished) to and from the internal nodes of the container are retained.
To remove all the containers in your scene
All the containers in the scene are removed, but their contents remain in the scene.