Can't drag and drop sprites to newly created animation file in animation editor

Hello,

After I create a new animation asset, the editor pops up. I see alot of youtube videos of people creating a new animation asset and then dragging and dropping groups of sprites onto the editor. But I think this is broken in 2020.1. When I try to drag and drop more than one sprite, the cursor maintains the "not allowed" icon. The workaround I found is drag and drop the group of sprites to the scene and it prompts to create a new animation.

 

I have the same problem in 2020.3.10f1
great solution - it works for me, thanks a lot!