Nested grids drag drop doesn't dispose when hovering over nested grid

I couldn’t reproduce this on codesandbox because dragging doesn’t seem to work there, so I made a case on stackblitz: https://stackblitz.com/edit/react-qeuac3?file=src%2FApp.js

When you drag the element into the first grid on the right side and the drag it to the left between 0 and 1 you can see that the placeholder doesn’t disappear.

It will also trigger 2 drop events, which can be fixed by adding event.stopPropagation();, but this causes the ghost overlay to remain and only to disappear when starting another drag.

[rogerfar]

@thomaspessato I updated my example here: https://stackblitz.com/edit/react-qeuac3?file=src%2Freact-grid-layout.js.

The only thing I did here was take the current master, build it and pasted the minified output in react-grid-layout.js. Then I added e.stopPropogation:

F(X(t), 'onDragLeave', function(e) {
                  e.preventDefault(),
                    e.stopPropagation(),
                    t.dragEnterCounter--,
                    0 === t.dragEnterCounter && t.removeDroppingPlaceholder();
                }),
                F(X(t), 'onDragEnter', function(e) {
                  e.preventDefault(), e.stopPropagation(), t.dragEnterCounter++;
                }),
                F(X(t), 'onDrop', function(e) {
                  e.preventDefault();
                  e.stopPropagation();
                  var r = t.props.droppingItem,
                    n = t.state.layout,
                    o = n.find(function(t) {
                      return t.i === r.i;
                    });
                  (t.dragEnterCounter = 0),
                    t.removeDroppingPlaceholder(),
                    t.props.onDrop(n, o, e);
                }),

[STRML]

Fixed in #1494