City Bars Example - No controller action after pop

[crema1984]

Dear sencha touch dev team and community,

I am very new at sencha touch and I tried the City Bars example with the Architect 2.1.0 588.
It works fine! But when i try to add a controller action to the call/more button on the DetailPanel like this

onButtonTap: function(button, e, options) {
  console.log('botton tap');
},

with following reference

control: {
   "#dataList": {                
       itemtap: 'onListItemTap' 
   },  
    "#callButton": {
       tap: 'onButtonTap'
   }      
}

it still works till I press the back button off the navigation bar (so MainNav.pop()). If I tap on a new listitem afterwards, the buttons on the new DetailPanel have no function. What is wrong with my code? The referencing?
In my opinion the example ends, where the interesting things begins

[crema1984]

After I created an issue report on the github repository (see https://github.com/SenchaArchitect/CityBars/issues/2), Phil Strong suggested me to use following component query

detailpanel button[text='Call']

I tried also:

detailpanel button[id='callButton']

which works fine, too.

Many thanks to him!