Dropbox Releases Update, Fixes Mac OS X Lion Integration Issue
The update also has a backport fix to a Linux issue wherein the tray menu sometimes becomes unresponsive.
Usually, when Dropbox issues updates, they just come down the pipe automatically, and most users don’t even know when it happens. However, it also can take a few weeks for an update to make it out to everyone, so if you’re an individual who does not want to wait for the auto-update to find its way to you, you can manually download and install Dropbox 1.1.40 for Mac (or Windows or Linux) from one of the links posted on the Dropbox forum or from the official download page.
Lion is still relatively new and was a significant change to Mac OS X; some hiccups with third-party integration is to be expected, but the Dropbox faithful no longer need to be concerned.