The drop down menus for "Default Frame settings for" under HDRenderPipelineAsset do not work. When clicking on the drops downs Null Ref errors are logged in the console.

Steps to reproduced
- Open Unity 2018.3.0b12
- Open the package manager > Advanced > Install Render-Pipelines.High-Definition.
- In your assets folder Create > Rendering > Render HDRP
- Select the "New HDRenderPipeLineAsset and try to use the drop down menus under "Default Frame settings for"
- Notice issue >> Menus are broken. Null reference errors appear in the log.

Broken Package: 4.2.0, 4.1.0
Working Package: 4.0.0 (This version does not have the "Default Frame settings for" menu.)
Tested Unity Version: 2018.3.0b12, 2018.3.0b11,2018.3.0b7