Change Dropping Behavior

[decaller]

I'm using this code on my Project here. It's using meteor to run though. The problem is when I'm moving object and want to drop it. Here I'm dragging it to be a child of 'besi'. As you can see the placeholder is not showing. But, if I drag it a bit under 'besi' parent the placeholder start showing. The placeholder show up and if I drop it, it would be placed on the intended place. The online deployed meteor can be visited here. I guess this is happen because it's made for vertical list though. Is there a workaround for this? Thank you...