Full screen kiosk app

I have made a kiosk application for Chrome, but despite being this kiosk I can not get it to full screen since I can still see the top bar and the OS tools. In background_main.js I have added the state line: 'fullscreen', as well as the permission in the manifest.json for 'fullscreen', but it still does not work. this is my background_main.js code:

 var runApp = function() {
      if (chrome.power) {
        chrome.power.requestKeepAwake('display');
      }
      console.log(config);
      chrome.app.window.create(
          config ?
          'exported_app_view.html' :
          'designer_view.html',
          {
            id: 'KioskDesignerWindow',
            width: 1100,
            height: 720,
            minWidth: 800,
            minHeight: 600,
            state: 'fullscreen' 
          },
          function(win) {
            if (!this.X) { return; }
            var window = win.contentWindow;
            window.onload = function() {
              this.$addWindow(window);
              var Y = this.X.subWindow(window, 'Kiosk Designer Window');
              this.DOM.init(Y);
            }.bind(this);
            win.onClosed.addListener(function() {
              this.$removeWindow(window);
            }.bind(this));
          }.bind(this));
    }.bind(this);