Hello,
it would be nice if there was a way to abort a mouse drag operation while it's being performed. To see what I mean, create an empty item and start dragging it. With the mouse button clicked, you now just HAVE to complete the drag operation and drop the item somewhere. There's no way out. Of course you can undo the move (or copy) operation after the fact, but sometimes the operation has multiple consequences (in particular, if several objects are selected when you start dragging), and they must all be undone one by one. It would be convenient to be able to just cancel the drag before it completes.
Windows Explorer allows you to abort the dragging by either hitting the Esc key or by pressing the right mouse button while the left is still pressed down. I thought Reaper would have such a way out, but after getting no reply to my how-to request
(here), I'm fairly sure a gesture such as this isn't available in Reaper at the moment.
Feature request: give us a way to abort a mouse drag while it's in progress.