Steps to reproduce:
1. Open the provided project "case_1197268-uielement-prefab-bug.zip"
2. Select "MyComponent" Prefab in the Hierarchy window
3. Notice the blue line and bold characters that indicate a difference between the scene Object and the Prefab
4. Right-click on the "youpi" property in the Inspector window

Expected: A dropdown menu shows up with an option to revert the value to the prefab value
Actual: A dropdown menu does not show up

Reproducible with: 2019.2.13f1, 2019.3.0b12, 2020.1.0a14
Could not test with: 2017.4.33f1 and 2018.4.13f1 due to errors being thrown in the Console related to UI Elements

Notes:
With IMGUI editors it is possible to:
- use Shift + right-click on any property to have a context menu that will show the property path in the console.
- right-click on some disabled properties while using Perforce integration to check out the asset.