How to set the sensitivity of a target zone in a captivate_9 drag and drop quizz

I’m currently designing a drag and drop quizz in an Arctic Geography lesson. I set smartshapes as targets but when I drag  the “source” on it, even I Let it a bit away of the shape, the answer is accepted… I’ve set the target with absolute position and 0 as Hit area padding… What am I doing wrong? Thanks