choicesMin&choicesMax properties do not work for dropdowns in the matrix detail panel

[andrewtelnov]

The following JSON doesn't work correctly:

{
    "elements": [
      {
        "type": "matrixdynamic",
        "name": "matrix",
        "rowCount": 1,
        "columns": [
          {
            "name": "col1",
            "cellType": "tex"          }
        ],
        detailPanelMode: "underRow",
        detailElements: [{
          "name": "q1",
          "type": "dropdown",
          "choices": ["a", "b"],
          "choicesMin": 1,
          "choicesMax": 5
        }],
      }
    ]
  }

"dropdown" doesn't have any visible choices in the detail panel, instead of ["a", "b", 1, 2, 3, 4, 5].