We've created a simple Dropbox Folder App on one user, and authorized it on another. Both users now have the same folders "App" and "App name".
Is these folders supposed to have the same content? Because on one of the users the folder is empty.
Are we missing something here?
It's not expected that two different users of a single Dropbox API app will automatically get the same content in their respective app folders.
The Dropbox API is built such that each user can link their own Dropbox account to an app in order to interact with their own files and folders. If the app uses the "app folder" permission, an app folder is automatically created in each user's account when they link the app. The app folder is empty by default, and the user can put files in their via any means they want (e.g., the API app itself, the Dropbox web site, the Dropbox desktop client, etc.).
A Dropbox API app folder is not like a shared folder. It does not sync across different user accounts, and in fact can't be shared with other users.
If you want all users of your app to have certain content in their account, you'll need to have your app upload the files to each account.