Slide In: Close button appears incorrectly

Using the "rounded" theme, the close button has a tail, which doesn't appear in the preview: https://www.dropbox.com/s/poe491jy7cj2ou5/Screenshot%202015-03-08%2016.27.16.png?dl=0

I'd really like to use this theme because, well, they both take up way too much space on the page, and this one is the better of the two in that regard.

We're pre-launching in a week. Any chance of a fix?

Thanks!