A clip drag/move operation is in fact a combined copy/paste operation, so: 1. The original copied/pasted clip in the clipboard is replaced by the clip you're moving 2. As the copy/paste within the move is complete (i.e. it was done as a single operation), the clipboard is cleared Any drag/move operation could essentially render the original clipboard contents invalid, so it's necessary to clear it before performing that operation. This is especially true in the case of audio, as