How to reproduce:
1. Create a new URP project and open it
2. Create a new Forward Renderer asset
3. Select it and in its Inspector add a new Render object to it
4. Under Shader Passes, click the "+" sign a couple of times to add new passes
5. Observe that the "-" button is greyed out and the pass elements themselves are unselectable

Expected result: the pass elements are selectable and the "-" button is enabled by default (If no pass is selected the last element is deleted on click)
Actual result: Shader Passes list elements are not selectable and thus undeletable, "-" button is locked by default (If no pass is selected the last element is deleted on click)

Reproduced in: 2021.1.0a1, 2020.2.0b3
Not reproducible in: 2020.2.0b2, 2020.1.6f1, 2019.4.10f1, 2018.4.27f1