How to reproduce:
1. Open the user-attached project “CurvyTest”
2. Create a new Empty GameObject and create another Empty GameObject as its Child
3. Add GizmoTest.cs Component to the Child GameObject
4. Observe the Scene View

Expected result: Gizmos are rendered in the Scene View
Actual result: Gizmos are not rendered until you select a Parent GameObject

Reproducible with: 2021.3.18f1, 2021.3.19f1
Not reproducible with: 2021.3.17f1, 2022.2.9f1, 2023.1.0b6, 2023.2.0a4
Couldn’t test with: 2020.3.45f1 (Script is not working)

Reproducible on: Windows 11 Pro