Lightbox issues

I have problem whit the lightbox. When i choose to edit an entry i open in a new page instead of open above the directory. It work in a couple of minutes but then it start playing with my mind. How can I get it to work again?

This is where I was making an example:
http://kontrolpanel.biketrading.dk/marker/

– Lars

https://ww.wp.xz.cn/plugins/gravity-forms-addons/