Folder level settings

[thermobob]

I tried to put the following:

"helm-intellisense.customValueFileNames": [ "k8s_dev-stek-vrfs.yaml" ]

in the settings.json inside a project, but I get this message:
"This setting cannot be applied in this workspace. It will be applied when you open the containing workspace folder directly."

Is this a bug? How can I apply the customValueFileNames setting at the folder level, when using an workspace?