Backbone.Marionette.Region extended to animate changing its content.

AnimatedRegion

var AnimatedRegion = Backbone.Marionette.Region.extend({
    show: function(view) {
        var that = this;
        this.ensureEl();
        this.close();

        view.on('close', function() {
            that.$el.addClass('transparent');        });
        $.when(view.render()).then(function() {
            that.open(view);
            that.$el.removeClass('transparent');

            Marionette.triggerMethod.call(view, "show");
            Marionette.triggerMethod.call(that, "show", view);
        });
        this.currentView = view;
    }
});