Listeners defaults aren't merged automatically

[llamerr]

There's already this thread https://www.sencha.com/forum/showthr...276#post484276

My question is - why listeners from defaults still (after 5-6years) aren't merged automatically with other listeners?

xtype: 'form',
defaults: {
  listeners: {
    specialkey: function( field, e ) {
      if ( e.getKey() == e.ENTER && field.isValid() && !me.queryById('acceptBtn').disabled ) {
        me.fireEvent('accept');
        me.close();
      }
    }
  }
},

items: [
....
{
  xtype: 'textfield',
  listeners: {
    change: function( field ) {

...

[llamerr]

I solved it like this

var defaultListeners = {
  specialkey: function( field, e ) {
    if ( e.getKey() == e.ENTER && field.isValid() && !me.queryById('acceptBtn').disabled ) {
      me.fireEvent('accept');
      me.close();
    }
  }
};

...

xtype: 'form',
defaults: {
  listeners: defaultListeners
},
items: [
...
{
  xtype: 'textfield',
    listeners: Ext.applyIf({
      change: function( field ) {}
    }, defaultListeners)
...

but my question stands - why apply ugly hacks and workarounds if it can be solved at the core of the problem instead?