So as to getting back to the app - every time you will be getting back from a 3rd party browser (any other browser than Sticky browser) your Master Password will be required. This is because in fact you have left the Sticky Password application before (it is running in the background, but you left it) and are using another application (the 3rd party browser). From security reasons, when Sticky Password is in background, it locks itself - the user might forget, that it is running in the background (it isn´t visible) and if someone else would get the phone, users data would have been compromised. You can change this behavior a bit and set the PIN protection in Settings - in such a case, Sticky Password will require a 4-digit PIN instead of the full Master Password. That´s a bit more convenient.