When color picker is selected from any component, editor throws the IndexOutOfRange exception and hides all components below it

Steps to repro:
1. Open a new project.
2. Add any components in hierarchy window which has a color picker option like "Directional Light", UI >> Image etc.
3. Select color picker in inspector windows.
4. Observe the error

Reproducible on: 2018.2.0a3

Works fine on: 2018.2.0a2.

Frequency:
Always.

Environment:
Occurs on Mac 10.12, Mac 10.13 and Windows 10