Would you mind sharing a link to the app? Many of us haven't had a chance to see many Seaside apps out in the wild. I think DabbleDB and Auctomatic are Seaside apps, but other than that I can't think of any.
Go to kayak.com, search for a hotel somewhere, find a rate from Reserve Travel and visit it; that's a seaside app.
I would like to, unfortunately it isn't a public application, and also contains medical information. Maybe one day I'll setup a demo account on a stand-alone server with fake data... but that is a really low priority (in fact, I just now came up with that, so its at the bottom of the list :)