If you have ever worked on Facebook apps as a developer, you will have a bitter experience with facebook because of their changes now and then to the API’s.

Let’s say you have created an awesome app for one of your clients. Hosted the app, everything is working good. Now when you add the app to that client page who has more than may be 15 or 20 apps listed in the tab zone. By logging as Admin/Developer you will see the app in the tab list.

But now let’s say that you added testers to test the app while it is in sandbox mode. The testers don’t see the app listed in the client facebook page. It is suppose that he/she should see it. For that there may be other reasons like SSL issue, app not properly setup in the developer area etc. But in case everything is good and still app is missing from the tabs list for testers.

The common reason for this is that facebook only allow 12 tabs at a time on a page, so a new tab for that app will not be there. But if the tester access the app directly through url, he can see the app.

So the solution to this will be to swap the newly created app within the 1st 12 apps. While logged in as Admin/Developer, go to the client page and list all the tabs by clicking on the button right hand side the tabs. That will show all the tabs. Now mouse over on the newly created app and click on the pencil/setting icon and swap it with any position you like but within the 12 tabs. Once you are done with that, check the page with tester account, and you will see the app listed there in the tabs. Facebook magic!