Trying to watch a value in a config section of datatype. from another value.

The value being watched is a multivalue. refered to as docTypeAliases.

The custom value has this code to do the watching

$scope.$parent.$parent.$watch('preValues[0].value', function (e,  args) {
var fString = '';
if (e != null) {
    console.log(e)
    angular.forEach(e, function (dt) {
        fString = fString + dt.value + ","
    });
    $scope.ProfileList = undefined;
}
GetAvailableBlocks(fString);
    $scope.loading = false;
});

The watch is triggered initally when creatinf or loading the dataType initally. But when a new value is added to the docTypeAliases value it never triggers.

Can any one surgest a better way.

I would normally setup an event trigger but as using umbraco default value editor I cant do that.

Further testing reveals that the trigger only gets triggered when I delete a value from docTypeAliases