There is a problem using the customtag functionality.

Steps to reproduce:

Create a new customtag that has "link" attribute. (or as a test/debug: edit ezdemo/settings/ezoe_attributes.ini.append.php and add Type=link to CustomAttribute_video_source then use the video custom tag)
Click on the folder to browse for the object to link to.
Select a node clicking the radio button.
ERROR: you get a blank screen.

Pull request:

https://github.com/ezsystems/ezpublish-legacy/pull/1007