Hi Santosh,
Thanks for your update.
With GridListControl celltype, the dropdownlist cannot be allowed to edit as it is the one derived from ListBox control. If you want to achieve the editing in dropdownlist thereby allowing the pencil icon to appear in rowheader of dropdownlist item, you can customize the dropdownlist embedding griddataboundgrid into it. This grid has similar look and feel as that of GridListControl.
Please refer to the sample in following forum thread in which the grid is embedded in dropdownlist.
http://www.syncfusion.com/support/forums/grid-windows/79614Also please refer to our browser sample in Syncfusion Dashboard, Grid samples -> Custom Cell Type -> Drop-Down Grid Demo in which embedding editable dropdowns in grid has been illustrated.
Regards,
Rajadurai