Total and Subtotal API returns no data with select-for-in expression

[Fengshuki]

Hi,

I have been experimenting with the Total and Subtotal API using the sample matrix (GitHub - microsoft/Powerbi-Visuals-SampleMatrix: demonstrates a powerbi matrix custom visual) which works just fine in itself.
However, after modifying the capabilities.json of the sample by adding an additional data role and changing the data view mappings for the rows of the matrix to use the select-for-in expression to bind to data roles to it, the visual is not able to retrieve any data. If the total and subtotal API is disabled, the data view mapping works just fine.

It seems like it is not possible to use the select-for-in expression with the Total and Subtotal API. Did anyone else encounter this problem? 

The modified parts of the capabilities.json are as following:

  "dataRoles": [
    {
      "name": "Rows",
      "displayName": "Rows",
      "displayNameKey": "Visual_Rows",
      "kind": "Grouping"
    },
    {
      "name": "Columns",
      "displayName": "Columns",
      "displayNameKey": "Visual_Columns",
      "kind": "Grouping"
    },
    {
      "name": "Value",
      "displayName": "Value",
      "displayNameKey": "Visual_Values",
      "kind": "Measure"
    },
    {
      "displayName": "Filters",
      "name": "Filters",
      "kind": "Grouping"
    }
  ],
  "dataViewMappings": [
    {
      "matrix": {
        "rows": {
          "select": [
            {
              "for": {
                "in": "Rows"
              }
            },
            {
              "for": {
                "in": "Filters"
              }
            }
          ]
        },
        "columns": {
          "for": {
            "in": "Columns"
          }
        },
        "values": {
          "select": [
            {
              "for": {
                "in": "Value"
              }
            }
          ]
        }
      }
    }
  ],

Best regards