I just upgraded our dev site to K2 2.10.0 and was really excited to see the new look of the back end item administration page.

But I cannot edit any K2 items. If I click on any of the item titles, where normally I would get the edit form, instead I get a KException Error | Fatal Error

Call to a member function isSite() on null.

The line complained about is:

.../administrator/templates/isis/html/com_k2/item/default.php:15

...which is: <?php if($this->mainframe->isSite()): ?>

I have tried clearing the cache, the expired cache, logging out and logging back in again. Before I start disassembling my site to see if there's an extension conflict, can anyone shed any light on what this error means?

I have the whole exception handling and error handling story if that would help.

I am able to edit K2 categories and users

Ah. I remember now. The override is to give new items a default expiry date. Blunt instrument for dealing with zombie content. Put it in so long ago I forgot all about it.

That fixes the problem... only now how to reproduce that functionality...

Thank you so much for the help.