Reproduction steps:

1. Open "FullscreenBug.zip" project
2. Build and launch Application
3. Click the "Fullscreen" Checkbox (Notice that it's in Windowed mode)
4. Click the "Fullscreen" Checkbox again (Notice that it's in Fullscreen mode)

Expected Result: The Checkbox remains responsive to clicks
Actual Result: The Checkbox becomes unclickable

Reproduced with: 2017.3.0a3, 2017.2.0b6, 2017.1.0p3, 5.6.3f1, 5.5.4p2