I know that this issue has been discussed earlier but the answer didn't help me.
I've installed the lite version and I'm also using the Simplicity theme from Olegnax (http://simplicitywp.olegnax.com/portfolio/). When clicking on a thumbnail it opens up in two separate windows. I have no other plugins installed.
Do you have any idea why this happens and what I might do to get rid of the "other" popup image?
I'm about to buy the Pro version but I need to know that this can be solved before I make the buy.
Unfortunately, I can't provide you with a link to the site since it's not live yet.
Thanks in advance!