Graph Settings window closes and Node Settings window opens up on expanding/closing Universal dropdown when property selected in Blackboard window.

Steps to repro:
1. Create a new URP template project.
2. Project Window > Click on "+" > Shader > Universal Render Pipeline.
3. Lit Shader Graph > Open Shader Graph > Blackboard Window > Float.
4. Select Float property > Graph Inspector > Graph Settings.
5. Expand / Close Universal dropdown.

Actual Result:
Graph Settings window loses focus on expanding Universal dropdown.

Expected Result:
Graph Settings window should not lose focus on expanding Universal dropdown.

Reproducible in:
2021.2.0a7, 2021.1.0b10, 2020.2.3f1 with Package version 12.0.0, 11.0.0, 10.3.2, 10.3.1.

Working Fine in:
2020.2.7f1, 2020.2.3f1 with Package version 10.2.2.
2020.1.17f1 with Package version 9.0.0-preview.72.

Note: Graph Inspector is not available in 2019.4.

Environment:
Occurring on Windows 10 & Mac 10.15.