Unable to see an added GameObject to any kind of track in the Timeline window, even though it gets attached.
Refer attached Video.

Steps to Reproduce:
1. Open the attached project.
2. Open Scene "Main"
3. Drag and Drop Cube GameObject into Timeline Animation Track OR
Drag and Drop AudioSource GameObject into the Audio Track

Actual Result :
Gameobject gets assigned but can not be seen on the resp. track.

Expected Result:
Gameobject gets assigned and can be seen on the resp. track.

Occurring on:
2020.1.0a18, 2020.1.0a15

Working Fine on:
2020.1.0a14, 2019.3.0f5

Tested on Package: Timeline (Preview 5) 1.3.0, 1.2.9

Environment:
Windows and Mac

License type: Pro