Reproduction steps:

1. Open "lockmouse_test.zip" project
2. Build for Linux Standalone
3. Launch the app
4. Move the mouse cursor around
5. Press the "Space" button
6. Move your mouse around, to see that it's locked
7. Press the "Space" button
8. Notice that the mouse cursor doesn't display

Expected Result: The mouse cursor displays after "CursorLockMode.None"
Actual Result: The mouse cursor doesn't display

Fixed in: 2018.3.0a9

Reproduced with: 2017.3.0b1, 2017.2.0f3, 2017.1.1f1, 5.6.3f1

Note:
Ubuntu 16.04

After "CursorLockMode.None", it seems that the cursor is still locked, but it just doesn't display. If in windowed mode, while locked you can't get outside the window, but if your in unlocked mode, even though it seems to be locked, you can go outside of the app

Not reproducible on Windows 10 and Mac 10.12.6