content fired several times on second click

i use colorbox_node to display multiple slideshows with media images or videos in a galleria.
my content type uses media ( https://drupal.org/project/media ) to store the images and videos.

my page has several thumbs to projects, a click on a thumb opens via colorbox_node the galleria in the colorbox.
on the first click everything is ok, i can see in the console log that galleria is firing up 1 object.
than i close the colorbox and click the thumb again, now i see 4 instances of the galleria firing up.
when i close it again and open it agin, i see 9 instances firing up, and so on, and so on...

how can i prevent galleria from firing multiple times?

any help is welcome,

thank you for this great modul

Volker