Problems when dragging down

[zhentonglee]

Hello Jexordexan,

I found a problem that when the heights of the sorted elements are not equal, dragging the higher-height elements downwards will cause problems where the position of the lower-height elements cannot be replaced. Fortunately, dragging up will not cause the problem.

For example, https://jexordexan.github.io/vue-slicksort/ Simple list,set the height of item1 to 300px, the height of item2 to be the same, the height of item3 to 300px, and then drag item1 downwards, you will not replace the position of item2 in item1, because item3 first slides up.

Cheers.