Files are not being added to assets folder if dragged and dropped in empty space below the package manager folder

Steps to Repro:
1. Create a new project
2. Drag and drop any file from desktop to project folder

Actual Result:
Unable to drop files in the empty space below package manager folder

Expected Result:
Files can be dropped in the empty space

Environment:
Windows and Mac

Occurring with:
2019.3.0a1, 2019.2.0a14, 2019.2.0a5

Working with:
2019.2.0a4, 2019.1.0f2