Removing / Hiding [+] when dealing with master / detail dataGrids

[StevenK]

I'm making use of 2 DataGrids on a form in a master / detail relationship. This is done through use of 2 DataTables within a DataSet and an appropriate DataRelation (setting up the link from the 'Master' DataTable to the 'Detail' DataTable).

When I display these DataSource / DataMembers in the grid I see a [+] sign in the left hand column in my 'Master' DataGrid. This can be expanded to show me the associated 'Detail' data entries in the same DataGrid.
Albeit that sometimes this is very useful - in this instance it isn't. I want to ensure that I am only able to display the 'Master' data entries in the 'Master' DataGrid.
How can I prevent the user from 'drilling-down' to the associated 'Detail' data entries within the 'Master' DataGrid.
Is there a property I can set or can I trap for it in some way ?
Any pointers would be appreciated.

Thanks in advance
Steve