group Input on a cached Group (Phaser 2.6.2)

[grinmonk]

this.inputEnableChildren = true;
this.onChildInputDown.add(() => this.onClick.dispatch(this));

I use the code above to track input on my Group. But when I cache the Group:

this.cacheAsBitmap = true;

...the signal stops working. Is there a way to handle input on a cached Group?