After saving a record in the Advanced Cataloging Editor, clicking on "edit items" opens the item form in a new tab, but it closes immediately.  This happens in a flash.  If you click on "view" to go to the record details screen and then click on Edit > Edit record, the same thing occurs.  This happens in both Chrome and Firefox.  Both of my browsers have exceptions in the pop-up blocker for the Koha servers I'm working with.  I experienced this on two different servers.  

If you right-click on "edit items" in the Advanced Cataloging Editor, copy the URL, and then paste it into a new tab, the item form opens without issue.

I consulted with a colleague, who believes the affected code is here:
http://git.koha-community.org/gitweb/?p=koha.git;a=blob;f=koha-tmpl/intranet-tmpl/prog/js/cataloging_additem.js;h=8c28e8398db0126d7c07e584f5475e357137d1aa;hb=HEAD#l13