Reproduction steps:

1. Open "linear-scene-gui.zip" project
2. In the Scene view click on the "Color Space" and change "Gamma" to "Linear"

Expected Result: The Color Space doesn't change the Editor GUI color (or least that dramatically)
Actual Result: The Linear Color Space Editor GUI looks unexpectedly light (washed out)

Fixed in: 2018.2.0b1, 2018.1.1f1

Reproduced with: 2018.2.0a6, 2018.1.0b12, 2018.1.0b1, 2018.1.0a7, 2018.1.0a4, 2018.1.0a2, 2017.3.0a7, 2017.3.0a4, 2017.3.0a1, 2017.2.2p2, 2017.1.3p2, 5.6.5p3
Did not reproduce on: 2018.1.0a1, 2017.4.0f1, 2017.3.2f1, 2017.3.0b1