Adding/editing doesn't work at all under Opera 8.02. Clicking the Add button appears to do nothing at all for new items. Refreshing the page, or visiting a different page, displays the following message in a red status area:

Couldn't add next action ""

Refreshing the page also confirms that the new item couldn't be added. Some of the other Ajax actions and effects do work correctly, so it isn't completely broken (I used Firefox to set up my items)