Regression - doesn't happen in 2017.3.0f1 and 2018.1.0a5, started to happen in 2018.1.0a6 and later (also in 2018.1.0b5)
I am on Windows 7 64b

How we can reproduce it
1 Open Unity and Create new project
2 Open "Player Settings" in Inspector (menu Edit->Project Settings->Player)
3 In Inspector open Other Settings tab and find Color Space dropdown
4 Click on Color Space dropdown to unfold it (sometimes you also need to scroll down and up content in Player Settings tab - so Color Space dropdown will be on another height) - please see attached video in comments

Actual results:
when you unfold Color Space dropdown - it makes the whole page to "jump up"

Expected results: page should not jump on unfolding dropdowns