Why I still use Chromium's "Application Shortcut" instead of Prism with Firefox 4 on Ubuntu 10.10

Here's one very important thing that I can do in Chromium's stand-alone Gmail window that I can't do in Prism's SSB window:

Drag and drop my attachments.

I hope this can be fixed soon.

Otherwise, Firefox 4 is my new favourite browser and well done to the Mozilla team for their splendid work.