Not watching model change in multiple

[Piernik]

Now You have code for watching of external model change:

controller.$render = function () {
    getSelection(function (selection) {
        if (isMultiple) {
            element.select2("data", selection);
        } else {
            element.select2("val", selection.id);
        }
    });
};

Problem is that it works only on strings or numbers: https://docs.angularjs.org/api/ng/type/ngModel.NgModelController

If we have multiple option turned on and make external change of model nothing happens.
Here is my workaround:

if (isMultiple) {
    scope.$watch(function () {
        return controller.$modelValue;
    }, function (newVal, oldVal) {
        if (newVal !== oldVal) {
            getSelection(function (selection) {
                if (isMultiple) {
                    element.select2("data", selection);
                } else {
                    element.select2("val", selection.id);
                }
            });
        }
    }, true);
} else {
    controller.$render = function () {
        getSelection(function (selection) {
            if (isMultiple) {
                element.select2("data", selection);
            } else {
                element.select2("val", selection.id);
            }
        });
    };
}

If is multiple then use deep watcher - if not stay with $render

EDIT:
I see that initial value for multiple is not working also - controller.$render(); in $timeout Here You have to trigger:

getSelection(function (selection) {
                    if (isMultiple) {
                        element.select2("data", selection);
                    } else {
                        element.select2("val", selection.id);
                    }
                });