I have a FB App which I created using Fandjango. It works fine if a user logs in to the application for the first time but in case user has used the app earlier and want to open the app, it opens up in independent browser and not in FB Canvas.
Any Idea how can it be corrected.
You're seeing this behavior because Fandjango caches the signed request in a cookie so you don't have to proxy every request through the Facebook canvas. There is currently no way to disable caching because it would introduce a very large overhead (several seconds per request) and make it very difficult for you to redirect the user to various parts of your application.