ListGrid.setEditorValueMap() is disappear immediately

I'm working on ListGrid edited fields to add comboxItem. During runtime i want to update comboxItem, so i used ListGrid.setEditorValueMap() to updated the comboboxItem.
While click on ComboBoxItem the dropdown is listed with updated values, but it immediately disappears.

Version used :smartgwt 4.0

Can you plz suggest me to fix this issue.

Thanks
Vasanth