@JOHNA You can achieve this without the calls to JET.Settings:

JET.ContainerDescription provides you with the theme in properties.

{
  "name": "Thomson Reuters Eikon",
  "logLevel": "debug",
  "version": "3.3",
  "containerVersion": "4.0",
  "productVersionInfo": "Desktop 4.0.36",
  "userAgent": "NET45,EIKON9.0.36485,SR0,ADF6.20162.04.21",
  "GUID": "4e638cc1e99644aa97c8868720a9c103",
  "capabilities": {
    "MenuItems": {},
    "Actions": {},
    "Events": {},
    "DragAndDrop": {},
    "Properties": {},
    "FullChromiumNavigation": {}
  },
  "properties": [
    {
      "theme": "Charcoal"
    },
    {
      "AppInfo": "{\"AppType\":\"WebApp\",\"Properties\":{\"JETTrustLevel\":\"Partner\",\"ServiceName\":\"Web Host App\"}}"
    }
  ],
  "windowInfo": {
    "windowId": "ba4c26e3-ecfa-4384-b3e8-0a7a591e5a1d",
    "isFlexViewer": false
  },
  "plugin": {
    "channel": "86f6da1c-5569-11e6-82b8-001c420552e0"
  },
  "major": 9,
  "minor": 0,
  "build": 36485
}

JET.getUserInfo gives you the preferred language:

{
  "FullUserName": "User name",
  "PreferredLanguage": "en-US",
  "UUID": "unique user id"
}

They should be:

• COMMON.REGIONAL_SETTINGS.UI_LANGUAGE
• COMMON.OTHER_SETTINGS.MOVEMENTCOLOR_UP
  
• COMMON.OTHER_SETTINGS.MOVEMENTCOLOR_DOWN
  
• COMMON.OTHER_SETTINGS.MOVEMENTCOLOR_LEVEL
  
• RDE_USER_CURRENT_THEME