tested on recent laptop in firefox and chrome... when adding new custom properties the action is getting slower which each one. At circa 15 it's unbearable and kills the browser
fixed upstream (http://gerrit.ovirt.org/gitweb?p=ovirt-engine.git;a=commit;h=1b36ba6e0247a6c07049adbf09c397fd0ae40768)
closing ON_QA bugs as oVirt 3.1 was released: http://www.ovirt.org/get-ovirt/