Presets Window doesn't disappear on closing "Curve" window, refer the attached video

Steps to repro:
1. Create a new Project
2. Hierarchy > Create > 3D Object > Tree
3. Select "OptimizedTree" in the Hierarchy
4. Inspector > Tree > Branch Group > Select
5. Open "Distribution Curve" under the Tree component
6. Click on "Setting" icon in the left-bottom corner
7. Close Curve Window

Actual Result:
Presets Setting window doesn't close on closing "Curve" Window

Expected Result:
Presets Setting window closes along with "Curve" editor window

Reproducible on:
2020.1.0a11, 2020.1.0a10, 2019.3.0b9

Working fine on:
2020.1.0a9, 2019.3.0b8

Environment:
Windows 10 & macOS 10.14