Pre-1.3 versions gave a popup. 1.3 gives a blank page.
The popup said something like "page cannot be found". Since 1.3 the popup is gone and a blank page appears.
It's probably the same bug that has to do with the cache system in Mozilla. The Grand Master Artist of IT discussed it a while ago. Hmmmm.... Lookie here: It's probably just a different manifestation in Mozilla related to [link|http://z.iwethey.org/forums/render/content/show?contentid=67937|this] and the links enclosed.
Why you're just seeing it now? Well, its temperamental. I only see it on zIWeThey.
HTH.
Cheers,
Scott.
