Thanks for that greate module!
I got it enabled on my website (www.ehrmann-photography.de) and am using the URL-function (http://www.ehrmann-photography.de/?theme=theme1). I created a content and included two links to two different themes, the block I put this in can be found at the top-right position.

If I now click on one of the links it changes the theme as expected, everything works fine until here.

Now comes my question and I am not sure if this could also be a feature-request:
Is it possible to actually only refresh the theme without jumping back to the frontpage of my site (As if i would change the theme via the dropdown-menu which can be found in the footer)? Alternatively, is there an easy way or some already existing tutorial on how to customize the css of that dropdown-menu?

This question might seem naive or anything, but my excuse is that i am barely a developer and therefore cant describe more than the actual process i imagine...