Hi Ignatius,
You said: I want to set up the child table also as a details view with its own binding navigator.
Based on my understanding, the root issue is that when you move to one record of the head table, there are several records in detail table related to header table, but you can only see the first record in the details view of the detail table.
To have the user be able to select a record of the detail table, besides adding the details view of the header table and the detail table, we can add a DataGridView view of the detail table to the form. Then we are able to select one row in that DataGridView to select a record of the detail table.
If you would not like to add a DataGridView to the form, but need to add an own navigator bar to the form. We can add a BindingNavigator control to the form and set its BindingSource property to the BindingSource of the detail table(detailsBindingSource). Then we can use this navigator to select a record of the detail table. You can get more about how to use BindingNavigator control from: http://msdn.microsoft.com/en-us/library/system.windows.forms.bindingnavigator.aspx
By the way, we can always save the data via the Save button of the head navigator to save the data. So it is unnecessary to add a new save button.
Let me know if this helps or not.
Aland Li
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