2 Column container problem

[ditorodev]

Hi guys, first of all, I want to congratulate you for such a good library.

I've encountered a bug on the library, working with 2 columns SortableContainer's, it has a weird animation when dragging some components.

To reproduce this problem just go to http://clauderic.github.io/react-sortable-hoc/#/basic-configuration/grid?_k=8abqva and edit the width of the div with the classes Showcase__style__list Showcase__style__stylizedList Showcase__style__grid to width: 350px

[chaomao]

I think it is solved in #617