There is no obvious "cancel" drop target while dragging items.
Nautilus 3.37.x (Flatpak nightly). Originally part of #1524 (closed)
As a minor issue in the DnD experience, there is currently no intuitive mouse-only way to cancel a DnD operation, also if an unwanted directory has been entered. Android solves this by putting a "mock" target called "Cancel" for app DnD operations from drawer to home screen, and a similar solution could be supported via in-app notifications or similar, but that is far from ideal.
Edited by António Fernandes