Activate panel with button click, white screen

[JavascriptParrot]

I would like to activate another panel from a button click, that works fine but after two times I got a white screen. Hit the button activates the other panel, after tap a button in that panel I'mn going back to the first panel. But when I tap the first button again the panel is hidden and the screen stay white. Anyone some useful tips?

My code

         control: {
            "button[go]": {
                tap: function (button, e, options) {
                    Ext.Viewport.setActiveItem({
                        xtype: button.go
                    });
                }
            } 

Tanks,
Gertjan

[mitchellsimoens]

What is the value of button.go? Are you using id or anything?

[JavascriptParrot]

It is a string and xtype.