Drag doesn't work as expected when the list has two column

Hello
Inorder to make my list to two columns, i gave the `ul` the below class :
```
.UnorderedList {
columns: 2;
-webkit-columns: 2;
-moz-columns: 2;
}
```
This turn the list into two columns, but when i try dragging, i can see that instead of the closest element or top or bottom elements, you can only change the order with the right or left elements !, how can i have a two column list which allows me to drag and drop any element to any slot ?
Thanks.