Selection model has such code:
Code:
fireSelectionChange: function(records, selected) {
        this.fireEvent('selectionchange', this.getView(), records, selected);
},
as the result, event is fired on selection model, not dataview...

For me worked such fix:
Code:
fireSelectionChange: function(records, selected) {
    this.getView().fireEvent('selectionchange', this.getView(), records, selected);
}
Fiddle: https://fiddle.sencha.com/#view/editor&fiddle/34bh

Is that correct fix, or this event should fire on selection model?