Running 3.5.2, Multisite.
Installed, created app @ dropbox.
Chose "Core" and then "Full".
Connected to dropbox via pop up, confirmed.
That then reloaded my wordpress homepage in the pop up window, triggered nothing in the meida uploader frame.
Clicking Dropbox Photos again in media uploader window just shows the authorization text.
If I click the authorize link again, dropbox window pops up, and the list of files/folders is shown there like you would see on the web.
Deleted app @ dropbox
Now getting fatal error when loading the dropbox tab of media uploader.
Uninstalled, for now.
Any issues with multisite, 3.5.2, or a change in the Dropbox app creation process (it seemed different than your instructions)?
Thanks, looks promising.