1. Create a new project
2. Delete any pre-existing Favorite categories
3. In the Project window select the "Scenes" folder
4. Drag and drop it onto the Favorites section

Expected results: new favorites can be added if there are no categories or folders in the Favorite section
Actual results: new favorites cannot be added if there are no categories or folders in the Favorite section

Reproduced on: 2017.4.37f1, 2018.4.18f1, 2019.3.4f1, 2020.1.0b1, 2020.2.0a2

Notes:
-Creating a new "Saved search" category solves the issue
-In 2018.4 the Favorites section is highlighted when trying to add a folder, but it is not added