Bug: Unable to drag-and-drop Favorites into folders

I used to be able to drag a new favorite on top of a folder and drop it in. Now it no longer works. I get the circle with a line through it:

If I drag it to a folder that already has links in it, that folder will open up automatically (which is new I think), and I can put the link in that way. But empty folders won’t open, and I can’t find any way of putting links in them.

Software version: 4.0b Beta 2.
Reported by Todd Phillips.
Forum link: https://logos.vanillacommunities.com/forums/t/8989.aspx
Status: fixed in 4.0b Beta 3