Add your own property to the built-in measure property

property_panell_add_to_measure.js

measures: {
  uses: "measures",
  min: 1,
  max: 6,
  items: {
    type: {
      ref: "qDef.type",
      type: "string",
      label: "Type",
      component: "dropdown",
      options: [
        { value: "line", label: "Line" },
        { value: "area", label: "Area" },
        { value: "column", label: "Bar" },
        { value: "none", label: "None" }
      ],
      defaultValue: "line"
    }
  }
}