contextValue 
  Context value of the comment thread. This can be used to contribute thread specific actions. For example, a comment thread is given a context value as editable. When contributing actions to comments/commentThread/title using menus extension point, you can specify context value for key commentThread in when expression like commentThread == editable.
"contributes": {
  "menus": {
    "comments/commentThread/title": [
      {
        "command": "extension.deleteCommentThread",
        "when": "commentThread == editable"
      }
    ]
  }
}Content copied to clipboard
This will show action extension.deleteCommentThread only for comment threads with contextValue is editable.