drag and drop mac editor issues

Hi,
i would like to ask if anybody has issues with drag´n drop inside the mac editor, for example:

A. try to drag any GameObject in the hierarchy onto another game object to reparent it.
B. Drag a Script onto a Gameobject.
C. drag a material to something
D. similar operations.

I am working in a school as a Unity teacher. Our classroom has iMacs from 2010. not all the same Modells, but nothing really new.

What happens ist VERY VERY OFTEN that onDrop freezes the editor for several seconds (10 to 50). After that the Editor gets responsive again, but the drag and drop did not do anything.
Means if we attempted to drop a Material onto the target Object it hangs and after the freeze it was not applied. This is super annoying.

Anybody got a clue?

Having similar problems on Mac. Multiple version of Unity: 5 series up through 2017.2. The way it works for me is that drag and drop pauses until you move your mouse again. Said another way, the drop action doesn’t actually cause the drop, wherever you move your mouse next is where it tries to drop it.

Happens to me every few minutes and has since I can remember. Infuriating to say the least.