Asks the delegate if the user is allowed to change the selection.
- macOS 10.0+
The table view that sent the message.
YES to allow the table view to change its selection (typically a row being edited),
NO to deny selection change.
The user can select and edit different cells within the same row, but can’t select another row unless the delegate approves. The delegate can implement this method for complex validation of edited rows based on the values of any of their cells.