List Tile View Sorting

Hi Experts,

I am working on Work Manager 6.2 development. We are using Windows platform. I am facing an issue in

List Tile View sorting. I am having one List Tile view which I have grouped using the 'Enable Groups' option,

which is working fine. Now I want to sort the list Items which are displayed in groups.

I am able to see one option - 'Allow sort : List can be sorted' but this option is disabled.

Could any one please tell me how I can achieve this. Your help would be much appreciated.

Thanks in advance,

Daya