JQuery mobile unable to change themes

[cesar-ioc]

I have a couple of buttons that when clicked, they change between themes "a" and "b", I'm using this script to change themes:

<script>
    $(document).ready(function() {
        $("#blueThemeButton").click(function() {
            $('[data-role=page]').page({theme:'a'});
        });

        $("#greenThemeButton").click(function() {
            $('[data-role=page]').page({theme:'b'});
        });
    });
</script>

This works as expected when change from theme "a" to theme "b", but it doesn't work if theme "b" is applied and I want to change back to theme "a".

Looks like I can only move forward in the themes list.

Here is a sample: http://plnkr.co/edit/Xa1yhopCTUYHZAlI7M0q?p=preview