AdvDBGrid with AdvDBLookupComboBox

I have a grid where I set the second column to use the ADVDBLookupComboBox. When I select or just click the drop down it erase the data in that field for that record, I'm not able to add anything from the drop down menu, what ever I select erase the field and leaves it blank. I looked in the examples and I don't see any thing different. I can edit any other column and it is saved. What did I miss.



Is a correct lookup relationship setup between the DBAdvGrid column field of the datasource and the field in the list source of the TAdvDBLookupComboBox?  There is a demo showing how to use TAdvDBLookupComboBox with TDBAdvGrid.
If a problem persists with a proper lookup relationship setup, please provide some detailed information, preferably a sample source project with which we can reproduce the problem here.

The Grid have  its DataSource set to a customer table, in the grid I have set column 2's EditLink to the FormControlEditLink and the Editor to edCustom. The FormControlEditLink is set to the TAdvDBLookupComboBox. The TAdvDBLookupComboBox DataSource is set to the same DataSource as the grids DataSource and  to the same DataField as the second column in the Grid, the ListSource is set to a table with Citys, the KeyField is set to the ListSource City DataField. 

I can send a sample source but I use Advantage Database.

but is there a lookup relationship set at dataset level between the fields in the datasource & listsource?

I'm not understanding your question. There is no relationship between the fields in the two tables, the only relationship is in the TAdvDBLookupComboBox

Please understand that a lookup field at dataset level should be defined. Please refer to our ADO sample that has such lookup relationship defined at dataset level.