I want my grid to be sorted by clicking in the header of different columns.

Situation:

The grid is a cDbCjGrid and the database is a SQLExpress.
There are no relations, just one single, simple table

The indexes are Fields prop.
1. ID unique numeric(10,0)
2. Name / ID char(20)
3. City / ID char(40)

The grids columns are ID Name City
I have
Set pbHeaderReorders to True
Set Ordering to 1
or Set Ordering to -1 No differens
Problem
When I click on the column-ID it does not sort
When I click on the column-Name it does sort
When I click on the column-City it does not sort

Question

Is there anything I have to do with the SQL-indexes? I have Refreshed them
When I look at the table in the Database explorer it sorts well.
When I use an embedded file with the same settings for the Grid, it sorts on all columns.