Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for an issue that matches the one I want to file, without success.

Issue Details

• Electron Version:
  • 4.1.2
• Operating System:
  • MacOS 10.14.4
• Last Known Working Electron version::
  • unknown

Expected Behavior

1. Give Signal Desktop focus in a conversation
2. GIve another application in that same MacOS desktop focus
3. Receive a message from someone in that conversation, see that it is visible in Signal Desktop but still unread
4. Switch to another MacOS desktop (or full screen app) and back to that desktop
5. Everything is the same as before - application from 2 has focus, Signal Desktop still has unread message

Actual Behavior

5. Signal Desktop has cursor blinking in message composition box, message is marked read, and application from 2 has focus. SIgnal Desktop mistakenly believes that it has focus and is acting like it.

To Reproduce

You can pull down Signal Desktop v1.24.1 right now and repro this. You can also repro this when you use Exposé. Signal Desktop appears to believe that it has focus when this happens as well.

Additional Information

Original bug: signalapp/Signal-Desktop#3310