private static void onDragOver(@Nonnull Region region, @Nonnull DragEvent event) {
		if (event.getGestureSource() != region && event.getDragboard().hasFiles()) {
			event.acceptTransferModes(TransferMode.COPY_OR_MOVE);
			event.consume();
		}
	}
Handle drag-over.

@param region
		Region dragged over.
@param event
		Drag event.
recaf-ui/src/main/java/software/coley/recaf/ui/dnd/DragAndDrop.java