[#27600] Fixed issue with navbar affecting views UI

To test:
* Goto admin/structure/views/view/events/edit
* Select rearrange for fields
* Note in javascript console there is a Javascript error
* Press Apply
* Note the URL is now admin/structure/views/ajax/rearrange/events/page/field and no longer on view

This PR fixes it showing the AJAX JSON results (and also the dialog popup wasn't the correct size).

![](https://www.dropbox.com/s/9mhei3nwwmovc11/Screenshot%202014-11-26%2013.15.55.png?dl=1)