I'm enjoying NextGEN, but my combination results in a bug.
When I activate NextGEN, Google+ plugin (http://wordpress.org/plugins/google/) and the DW-Minion theme (http://wordpress.org/themes/dw-minion) an empty but wide iframe (from Google) puts himself with a high z-index, avoiding the interactivity.
You can find more details in this discussion: http://wordpress.org/support/topic/google-plugin-ruins-dw-minion-with-ff-1?replies=16
I don't know why NextGEN, even if not in use in a page, can be responsible, but it is so: if I disable NextGEN the problem disappear.
I wrote to the theme author (with no answer) and to the plugin author (with no solution). So, maybe you are able to investigate.
Can you check the odd combination?