Using querySelector to find nested elements inside a Polymer template returns null

Question

I\'m trying to use paper-tabs inside new element (tabs-list) but after print tabs I can\'t use querySelector to change selected one.

Element code (withou

Answer 1

And to toggle the iron-collapse elements inside the dom-repeat I use

 _showdetail: function(e){
    Polymer.dom(e.currentTarget).querySelector('#collapse').toggle();
},