Toggle icon for scene visibility doesn't appear when mouse is hovered on Scene in Hierarchy view.

Steps to Reproduce:
1. Create a new project.
2. Hover mouse on scene name in Hierarchy view.

Actual Result:
Toggle icon for scene visibility from Hierarchy doesn't appear.

Expected Result:
Toggle icon for scene visibility appears when mouse is hovered on Scene in Hierarchy.

Note: Refer attached image.

Reproducible on:
2019.3.0a3

Works fine on:
2019.3.0a2, 2019.2.0b3

Environment:
Windows and MacOS