enumerateObjectInstances not getting called

Hi,

I've added the following to my capabilities.json file:

  "objects": {
    "testObject": {
      "displayName": "Test object",
      "properties": {
        "testProperty": {
          "displayName": "Test property",
          "type": {
            "bool": true
          }
        }
      }
    }
  }

and I've edited my visual's enumerateObjectInstances method to perform 

console.log("test");

However, nothing ever gets logged!

In the comment above the method it says that it gets called for each object in the capabilities file, so how come it's not getting called?

Thanks