How to extend components?

[#1]

I am wondering if its possible to change the ref attribute of measure component? I tried with this alteration

measures : {
  uses : "measures",
  min : 1,
  ref: "KFMeasuresList",
  },

But the add button is greyed out. Do I need to change something else or is it not possible this way?

I have implementet my own array and it works except for the expression popup when you add an item.

kfMeasureList:  {
    type: "array",
    translation: "Row measures",
    ref: "kfMeasureList",
    min: 1,
    allowAdd: true,
    allowRemove: true,
    allowMove: false,
    addTranslation: "Add row measure",
    grouped: true,
    sourceType: "kfMeasure",
    itemTitleRef: "label",
    items: {
        rowMeasure : {
            type : "string",
            expression : "always",
            expressionType : "measure",
            ref : "expression",
            label : "Measure",
            defaultValue : "",
            change : function(a,b) {
                    var c = a
                    if (c.label == '') {
                        c.label = c.qDef
                    };
                    return updateMeasures(a,b);
            }
        },
        rowLabel: {
            type: "string",
            ref: "label",
            label: "Label",
            show: true,
            defaultValue: ""
        }
...

Do I have to create my own component for this to make the popup appear?

Cheers

Karl