Prevent dropping a track on to a playing deck

I'm using a DDJ-RX with Rekordbox on my laptop. When I used Traktor I was able to control a setting that prevented me from dropping a track on to a playing deck. I can't seem to find how to do this in Rekordbox. I've looked through the manual and these forums (even an older post with someone using the T1) but can's seem to figure this out. Help?