Reproduction steps:
1. Open project "Test Native Screen"
2. Go to "PlayerSettings"
3. Choose "Resolution and Presentation"
4. Set "Default Is Full Screen" to true
5. Set "Default Is Native Resolution" to true
6. Set the "Display Resolution Dialog" to "Hidden By Default"
7. Set the "Mac Fullscreen Mode" to "Fullscreen Window"
8. Build "Test" scene in "Development Build"
Note: Error window should pop up.

Notice differences between what Screen.Resolution return and Screen.width x Screen.height.

Expected: Both show the same values (i.e. "1920 x 1080 @ 60Hz" and "1920 x 1080")
Actual: The values differ. Screen.Resolution return Native resolution, however, actual screen width and height values are smaller.

Versions Reproduced: Unity 5.0.4f1, 5.2.4f1, 5.3.0f4, 5.3.4f1, 5.3.4p5, 5.4.0b12, 5.4.0b14, 5.4.0b15, 5.4.0b16

Note: On Windows everything works fine.