grid column disappear after sizable and setModel with frozen column

http://zkfiddle.org/sample/2gk0lav/1-Test-Frozen

Reproduce steps:

1.click "get all data to grid" (setModel)

2.Scroll to right until test5 hided.

3.change test6's size

4.click "get all data to grid" setModel) again

5.Scroll to left and the test5 is not showing anymore.