After creating new Animation then during adding a Property, 'Property window' remains to stay open, on closing the Animation window. refer to the attached video

Steps To Repro:
1] Create a new project.
2] Window > Animation >Animation Window
3] Hierarchy > 3D object > Cube
4] Animation > Create New Animation
5] Animation Window > Add Property
6] Close the Animation window

Actual Result:
'Property window' remains open after closing the Animation window.

Expected Result:
'Property window' should close as soon as the Animation window gets closed.

Workaround:
On clicking anywhere in the Project screen will vanish 'Property window'.

Occurring on:
2020.2.0a7, 2020.1.0b5, 2020.1.0a23

Working fine:
2020.1.0a22, 2019.3.6f1

Environment:
macOS 10.15+