Google rolled out a new version of Gmail with different code -- we've now updated the feature to use the new code. That version should not be working. (You may need to clear your cache and restart your browser if reloading Gmail doesn't fix it.)

We've set up a status page to keep track of all the different versions of Gmail's code (and whether or not we're supporting them yet):

If you encounter issues with this feature in the future, please check this page to find out if your Gmail version is supported, and how to let us know if it's not supported yet.

Please let me know if you continue to experience problems!