Cannot move learning objects into folder

I created a folder and I cannot move learning objects into the newly created folder. Sometimes I cannot move specific learning objects only, sometimes I can move none at all. I am co-author of the learning objects.

What version of Xerte are you using and what browser?

The arrow should point to the folder while dragging (I don't see that in your screencast).

I am using 3.12.1 with the latest version of Microsoft Edge 114.0.1823.51.
I drag the mouse pointer over the folder, but it always jumps above or below the folder. It is shown in the screenshot. It's actually not a screenshot, it's an animated GIF, so you can see what's happening.

I know that it is an animated gif, and I saw that it jumps over the folder..I've tried Edge (Versie 114.0.1823.51 (64-bit)) myself, and for me it works fine (as does chrome).

So I really don't know. We're at 3.12.12 at the moment, but nothing has been changed to this part of the code as far as I can tell.

I was just working in a 3.12.8 installation and saw the discussion so tested myself too in both Chrome and Edge and can't reproduce this. I noticed the OP referred to co-author access so just tested in another installation 3.12.6 with a project where I'm co-author and that works fine too.

I guess questions I would ask the OP:
As this is a 3.12.x installation is it an upgrade and therefore did you run upgrade.php?
Have you cleared offline files/cache?
If no to either of those then do that and try again.

I have now upgraded to version 3.12.12 from github, ran upgrade.php (we always did), and tested it in a freshly installed Firefox but still have the same issue.
BTW, is it normal that after the upgrade it now shows only 3.12, no minor version anymore?