I have a DataGridView column which will not allow me to set ReadOnly=False.
I can change the setting from True to False in the designer but, as soon as
I click OK and then go in and look again, it has gone back to True.

The underlying SQL which feeds the DataSet, BindingSource, etc is not
updateable. I suspect that might be the cause of what I am seeing.

In this case, I need the user to be able to change values in the
DataGridView, although they will never get written back to the database
through the BindingSource, TableAdapter, etc.

Clues on how to get ReadOnly=False to stick would be greatly appreciated.