InputModeUIOnly Causes User Interface to Become Unresponsive When Entering Fullscreen on Macs Only

The licensee is setting their game to InputModeUIOnly and ShowMouseCursor in the HUD blueprint resulting in the user interface becoming unresponsive when entering fullscreen on a Mac but not on a PC. They would like to know if this is a bug, expected behavior and/or if this is the correct way to manage these settings.

NOTE:

1. The bug does not occur on Windows
2. If you change the checkbox's changed event in the widget blueprint to set the mode to Windowed Fullscreen instead of Fullscreen, then the bug does not occur.
3. The bug also occurs in a cooked game.

Regression: No

1. On a Mac System running Sierra, download the licensee's sample project from the following shared link: [Link Removed]
2. Load the attached project in the editor
3. Begin PIE as a standalone game
4. The game will begin windowed, and the checkbox not checked
5. NOTE: the buttons respond to mouse input, changing their rendered state
6. Check the checkbox. The game will transition to fullscreen
7. RESULT: The game no longer responds to mouse input. Neither the checkbox nor the buttons respond.
8. EXPECTED: The game to still respond to mouse input in fullscreen mode on all platforms.