Sortable: Dragging sortable item onto linked list and scrolling to that list causes flickering

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If you have a scrollable element that contains connected sortable lists (or div's table's etc), when you try to drag from one list to another connected list and at the same time scroll this new list into view it causes a flickering between items on that 'active' sort list. This appears to be an issue in the latest FF, latest Chrome and IE8 - possibly more.

I found that this isn't an issue in version 1.8.9 but is in 1.8.12 as illustrated here:

​http://jsbin.com/iruqa4/17/edit

^{Swap JQuery UI source files in code view to see the issue and fixed solution.}

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I've noticed now that in the older version when you slightly edge an item over to a connected list it doesn't fire the 'over' event (and move the list over) even though the item is now on that list. This isn't an issue with the latest 1.8.12 version however.

[petersendidit]

Still is a problem in 1.9.1 ​http://jsfiddle.net/petersendidit/YSeut/

[tj.vantoll]

This is working fine in master ​http://jsfiddle.net/tj_vantoll/cyQHK/4/.

The problem was apparently fixed in 1.8.24 because I see the issue in 1.8.23 (​http://jsfiddle.net/tj_vantoll/yZQ8T/) but when I bump the version up to 1.8.24 it goes away. Not sure which of these changes would've affected this ​http://jqueryui.com/changelog/1.8.24/.

The test case was temporarily re-broke because of #8792 (which is why petersendidit commented as such above).