I have used the default slideshow of magento introduced in 1.9. in my 1.9.2.4 local installation. Works fine in my default rwd theme with the same code etc from cms. But switching to my theme which is a duplicate of the rwd theme, does not. I haven't edited no code related to the slideshow. when I load the site on my laptop then resize the site down below 771px it does work. But, load the site with the browser already at 771px or below it does not. Very strange, and in trying to debug no errors are being shown.