Hello everyone,

I'm struggling with event propagation issue and I'm asking you guide...

I'm handling with: Ext.ux.form.MultiSelect and Ext.ux.form.ItemSelector,
the last drive from first, here:

Code:
Ext.define("Ext.ux.form.ItemSelector", {
    extend: "Ext.ux.form.MultiSelect",
The super class handling already with selectChange event and I don't want to touch the existing behavior in the super class, I just want to add functionality or attaching that event from the sub class,

Here:

MultiSelect.js
Code:
Ext.define("Ext.ux.form.MultiSelect", {
    extend: "Ext.form.FieldContainer",
    .
    .
    .
    onSelectChange: function(a, b) {
        if (!this.ignoreSelectChange) {
            this.setValue(b)
        }
    },
    .
    .    .
});

ItemSelector.js
Code:
Ext.define("Ext.ux.form.ItemSelector", {
    extend: "Ext.ux.form.MultiSelect",
    .
    .
    .    viewModel: {
        data: {
            _addAll: true,
            _add: true,
            _remove: true,
            _removeAll: true
        }
    },
    .
    .
    .
    initComponent: function() {
        // CATCH THE onSelectChange EVENT IN THE SUPER CLASS TO FIRE setButtonsState
    },
    .
    .    setButtonsState: function() {
        var b = this,
            vm = b.getViewModel();


        vm.set('_addAll', ...);
        vm.set('_removeAll', ...);
        vm.set('_add', ...);
        vm.set('_remove', ...);
    },