All properties dropdown icons are missing when preset of "Mesh Renderer" is created, refer attached screenshot.

Steps to repro:
1. Create a new project.
2. Hierarchy > right-click > 3D Object > Cube
3. Create Mesh Renderer Preset

Actual Result:
The dropdown icons are missing in Mesh Renderer Preset.

Expected Result:
The dropdown icons are visible clearly

Occurring on:
2020.1.0a17, 2020.1.0a16, 2019.3.0f3, 2019.3.0f2

Working fine in :
2020.1.0a15 , 2019.3.0f1

Environment:
Windows 10 and macOS 10.14