I've installed SBOMscanner using the UI extension using the default options. As a result of that, the backend is installed inside the cattle-sbomscanner-system namespace.
When adding a new registry, the dropdown menu doesn't allow to select this namespace.
Adding the namespace by hand is also not working:
When pressing "enter" the text field goes back to being empty.
The only workaround is to edit the YAML (or create the registry via the k8s API).