I ran across a problem with using a viewreference inside of a Panel via the cTools Page Manager. As there are numerous modules in the process chain, I am not sure where to report it. So I am starting here.
Essentially, when I try to add a node viewreference to pane, it looses it "Field Format" upon submission. These are the errors I get:
warning: Invalid argument supplied for foreach() in /home/drupal/drupal-6.15/sites/all/modules/cck/includes/panels/content_types/content_field.inc on line 172.
An illegal choice has been detected. Please contact the site administrator.
The first error indicates that it is something with CCK, which is why I am starting here.
Attached are screen shots of this in action. I've also created a quick screencast if you want to see this error in action - http://www.nhm.ku.edu/viewreference-in-panels-bug.swf