Nextgen – gallery overflow?

Hello,
if this post is on the wrong place, please relocate it.
I’m using wp and ng in the latest versions and encountered a problem when placing a gallery in a single article. The gallery is identified by the gallery-id.

when a reader clicks on a picture from the gallery and uses the left or right arrows to navigate through the gallery he is also shown pictures from other galleries.
What I’m doing wrong?
If you want to see this unfeature take a look on my site (it’s only a testsite)