This had been bothering me for a while. Every once a while, the Drag & Drop would all of sudden stop working on me. When it happened, I would have to reboot my computer in order to get this feature back. Since I am a heavy drag & drop user who is also not a big fan of reboot, I decided to investigate.
Turns out, here is the fix, a very easy and quick one:
Press Esc Key Once
It’s just that simple. Can you believe it?
In case this doesn’t work, you can also try pressing Ctrl, Alt, or Win key several times and see if it helps.
/tip hat to this guy/