[Feature Request] Drag from outside and into grid item?

[jqhr]

Hi, I find https://jbaysolutions.github.io/vue-grid-layout/guide/10-drag-from-outside.html. It's very very great for me. Now, I have another question--- drag a box from outside and drop in grid-item.oh, I mean, the layout contain an grid-item component which is vue grid component too, I want drag an item from outside into this grid-item. I trid any solutions, but failed. How can I do?