Tab in Cell-Edit ListGrid with DateItem

Hi,

I found a problem with moving in a ListGrid by using the tab key when using cell edit.

Steps to reproduce:
* go to http://www.smartclient.com/smartgwt/showcase/#grid_editing_cell
* switch oder of "Independence" and "Population" columns by using drag and drop on the column headings
* click into the cell of "China" for column "Independence"
* press "TAB"-key

expected behaviour:
* switching focus to "Population"-column

experienced behaviour:
* focus is lost somewhere, cell editing stopped

Environment:
* the showcase uses currently SmartClient Version: v9.1p_2014-09-04/LGPL Development Only (built 2014-09-04)
* I'm using Firefox 24.3.0 on Windows 7

Row-Edit works fine.

Any ideas how to solve this?

Thanks in advance!