select(multiple): rendering bug when model array is changed

I was trying to solve a general problem with the md-select directive: It is necessary to update the selected value(s) when the array list changes (to avoid remain values that does not exist in this current list).

I achieve it within a directive declaration, but I found an important trouble:

When I change selected value(s), the component is not automatically rendered. What do I need to implement for it?

Here is a testing demo.

[Splaktar]

I don't fully understand what your custom directive is trying to do. Can you please explain the initial problem that you encountered that let to your need to create that directive? Do you have a demo of what is not working properly w/o that directive?

You may also want to take a look at https://material.angularjs.org/1.1.24/api/directive/mdSelect#selects-and-object-equality, including the part about using ng-model-options="{trackBy: '$value.code'}".

Let's go to a real example (to understand this)!:

In a multiple md-select, you select several options. After, the array list is replaced by another new one. What is happening? Well, the current selected values is not related with the current list because these was previously defined.

What I am trying to do is avoid this.