Editor hangs when dragging and dropping

Hi all, I’m trying to figure out if this is my setup or a general bug with Unity. I’m on a Macbook Pro, mid 2012 with 16gb ram. Running Unity 5.4.1f1 Personal.

The issue is not always present, but occasionally when I drag and drop something, whether it be an object, material, script, etc., doesn’t matter, the editor seems to hang until I move my mouse around after releasing the left mouse button. Sometimes the drop doesn’t stick and nothing was moved/applied, other times it does.

I get that occasionally as well. Restarting unity clears it right up for me. It usually occurs if I have had the app open for a long time.