Storyline - Bugs in my drag-and-drop carousel slide

Hello! 

So I have a drag-and-drop slide, because there are 8 objects to drop I wanted to put this in a carousel so all of them will fit. And here comes an issue. 

In Drag & Drop options firstly I have ticked this option. I wanted this so no one can put an item on top of an item in the same drop target.

But this didn't work the picture that was below the dropped item was moved back to the carousel but when I was moving the carousel with the arrows this item was still there. Some of them from the top part of the carousel just simply disappear. So I had to untick this option.

Without this option ticked it's going like this. All the dropped items back on the carousel appear in the same place and when I'm using the arrows they go above the top layer with the 'Next' and 'Previous' buttons. 

Does anyone know how to fix those issues? How to make it more smooth?

The correct order is:

01. Corridors

02. Doors

03. Floors

04. Hazards

05. Lightning

06. Signs

Incorrect ones are: Ground and Vehicles

I have attached my storyline file as it might be easier for you to see that and check on your own. Thank you.