I installed K2 in a new site and configured it to add items from the frontend; when I press the "add item" button in the front end it opens the editor in the same window, without the lightbox popup. 
The cancel button doesn't work, and when I press the save button it doesn't redirect me to the original page, but keeps on the editor page.

Thanks for your help.


Edit: it seems to be like this: community.getk2.org/forum/topics/editors-window

Check your page for javascript errors.

Where can I find the "add item" on the front end?