In the prefab of game object, when Layers are selected from the dropdown then dropdown closes and it overlaps with Layer text

Steps to reproduce:
1) Create a New project
2) Hierarchy > 3D Object > Cube
3) Create a Prefab.
4) Hierarchy > Cube > Inspector > Layer > TransperantFX .

Actual result:
Input filed of Layer's dropdown is overlapping with its Label (Layer)

Expected result:
Layer's dropdown and its Label (Layer) doesn't get overlaps on creating its prefab

Reproducible in:
2020.2.0a19.

Working fine in:
2020.2.0a18, 2020.1.0f1

Environment: Both Windows and Mac.