While some app lockers do try to address this, several others seem to disregard it. That said, searching out one that is considerate would be one way to proceed. Yes finding a launcher that offers contrl over how recent apps display should help. Alternatively, you can let an App called tasker on the App Store to handle this. It is not free but it is said to do the job. We are as well hoping to try and address this feature on the LC AppLock. Hopefully by force closing all background apps if a locked app is launched without a correct pattern/PIN input.