Over event isn't propagated if nested droppable doesn't accept draggable under a certain scenario

[Deepankar Jain]

The steps below are applicable for the following jsFiddle, ​https://jsfiddle.net/deepankarj/60zz9zgb/.

Steps:

1. Click on and drag Draggable 1 onto the inner droppable of Droppable 3. Continue to hold Draggable 1, do not release it.
2. Note that when Draggable 1 is on the inner droppable and the pointer is fully over the area of Droppable 3, the outer Droppable 3 is highlighted, which is expected.
3. Move Draggable 1 beyond the bounds of Droppable 3 and release it so that it's resting entirely in whitespace.
4. Click and drag Draggable 2. You only have to drag it to some random whitespace spot, not on a droppable.
5. Release Draggable 2.
6. Grab Draggable 1 again and drag it onto the inner droppable of Draggable 3. Continue to hold Draggable 1, do not release it.
7. When Draggable 1 is on the inner droppable and the pointer is fully over the area of Droppable 3, take a note of the state of the outer Droppable 3 container.

Expected results:

• The outer Droppable 3 container is highlighted when Draggable 1 is entirely on the inner droppable and within the bounds of Droppable 3.

Actual results:

• The outer Droppable 3 container is not highlighted when Draggable 1 is entirely on the inner droppable and within the bounds of Droppable 3.

Notes:

• If you debug the issue, it turns out that simply dragging Draggable 2 results in some state changes in Droppable 3, such that event propagation no longer works as expected when Droppable 1 is on the inner droppable.
• Console logs have been added to this jsFiddle to help highlight this issue.

[Deepankar Jain]

This issue seems like it's related to #10111, but the scenario is slightly different. Therefore, I've raised a separate issue.