How to reproduce:
1. Open the user’s attached “MultiSelectCurveBug.zip” project
2. Open “ParticleSystem.prefab”
3. In the Hierarchy, select all 3 “PS1” GameObjects
4. In the Inspector window, open the “Velocity over Lifetime” tab
5. Select any of the Linear axis curves
6. Select a point or its handle and try to move it

Expected result: Focus of the point or handle is not lost when moving it, and there are no errors when moving the handle
Actual result: Focus of the point or handle is lost when moving it, and an “NullReferenceException“ error appears when moving the handle

Reproducible with: 2021.3.33f1, 2022.3.16f1, 2023.2.4f1, 2023.3.0b1

Reproduced on: macOS 13.6.3 (Intel)
Not reproducible on: No other environment tested

Note: not reproducible again if not exiting the prefab edit mode