In the Sprite Editor window under Skinning Editor, Bones, Geometry, Weights, Visibility panels background layout with its title is missing also some sliders and property names of fields are not visible.

Steps to repro:
1. Create a new project with a 2D template.
2. Window > Package Manager > 2D Animation.
3. Import any sprite into the Unity project.
4. With the sprite selected in Assets, open Sprite Editor.
5. Sprite Editor > Skinning Editor

Actual result: Bones, Geometry, Weights, Visibility properties are missing.

Expected result: All properties should be visible.

Reproducible with: 2020.1.0a20
Working Fine with: 2020.1.0a19, 2019.3.0f6.

package version found: 4.1.0, 4.0.1, 4.0.0

Environment: Windows 10 and macOS 10.14