FB Patch is a patch for Facebook on the iPhone that will correct a bug or error in the application itself. At the close directly from the multitasking bar asks you to log in again this every time the closures from the multitasking dock but thanks to this patch will not happen again.
You will also need Jailbreak on iPhone and obviously facebook application installed. It is free and you can download from the BigBoss repository.
Once added only have a switch to enable or disable if this bug is resolved, that simple button.