Portfolio Slideshow Plugin: Mobile Glitch

Hi All:

I have just discovered an issue with the mobile navigation on a site I’m building. Guessing this is a case of a plugin not playing nice with the structure of the site. The theme is “Publish” and the plugin is “Portfolio Slideshow.”

http://nataliesmith.info/

On a smartphone, the navigation works perfectly. However, on an interior page in which the plugin is active, the drop down glitches. For instance, on the page “Recent”, the dropdown disappears behind the image, instead of layering on top of it.

Anyone have any idea what the issue might be? Hoping this is just a simple css fix.

Thanks!
George