Serializer.findProperty("matrixdynamic", "rowCount").defaultValue = 0;
  const survey = new SurveyModel({
    elements: [
      {
        type: "matrixdynamic",
        name: "matrix",
        columns: [{ name: "col1" }]
      }
    ]
  });
  survey.data = { matrix: [{ col1: 1 }] };
  //matrix has empty visible rows