In 1.8rc1 the stack option has changed from hash to selector losing the option to set the z-order min. In my opinion this is mistake.

The old way you could have two types of draggables, type A and type B, and keep all type A's on top of type B's by setting B's min to 0 and A's min to be slightly higher then the number of B elements you could reasonably expect. Each time a drag of type B occurred the z-order of all the B elements was recalculated starting at 0, never approaching the A min.

The new way, the min is automatically calculated as the current lowest z-order of the type being dragged. Every time you perform a drag the z-order increases (even if you just drag the same element multiple times). It is now much more likely that type B's z-order will get so high that it runs into type A's z-order and you get B's on top of A's. The longer you run the app, the higher the z-orders get. Of course you could set the lowest A z-order at such a high number that the user would have to perform millions of drags to cause this problem but as you attempt to have multiple "levels" this quickly becomes silly.

This change is also a breaking change, causing code written for 1.7.2 to break. It seems silly to introduce a breaking change that also reduces functionality. I suggest this change be reverted.

Stephen