Error when adding widget filter (following along to Chris Part 1)

Huge thanks to Chris for an excellent follow-along presentation yesterday.  So many eye-opening moments.

However, my analytics tripped me up right at the start of the first exercise of adding a widget level filter (Campaign) against the dashboard that had Campaign as a dashboard level filter.

When I click OK on the widget level filter, I get an error with the message 'An item with the same key has already been added.' and a big red warning diamond.    


Did anyone else get this?   Any thoughts on what I've done wrong?

Everything else in the training session worked just fine.

many thanks

Alison