OSX standalone player crashes on losing focus from Resolution Dialog.

Steps to Reproduce
1. Create a new project
2. Make sure that "Display Resolution Dialog" is enabled. (Edit > Project Settings > Player > Display Resolution Dialog > Enabled)
3. File > Build Settings > PC, Mac & Linux Standalone > Switch Platform > Build And Run
4. Switch focus to another app

Actual Result:
Player crashes on losing focus from Resolution Dialog.

Expected Result:
Player's Resolution Dialog is accessible when it's focused back.

Reproducible on:
2019.1.0a11, 2019.1.0a10

Works on:
2019.1.0a9, 2018.3.0f1

Environment:
Only on Mac

Note:
1. If Display Resolution Dialog is disabled then a player doesn't crash as Resolution Dialog doesn't appear
2. Refer attached video