The sort icon direction is not synchronized in model

Steps to Reproduce

http://zkfiddle.org/sample/u23fap/1-ZK-4283

1. Click the column "Name" to sort
2. Both "Name" columns on the listboxes should have a sort ascending/descending indication icon

Current Result

Though the sort result is synchronized, the sort icon isn't.

Expected Result

The sort icon should be synchronized too.

Debug Information

Workaround