Why is -didDeselectRowAtIndexPath not being called?

the documentation of tableView:willDeselectRowAtIndexPath: also says that

This method is only called if there is an existing selection when the user tries to select a different row. The delegate is sent this method for the previously selected row. You can use UITableViewCellSelectionStyleNone to disable the appearance of the cell highlight on touch-down.

It not worked for we when I used UITableViewCellSelectionStyleNone.

If you call deselectRowAtIndexPath:animated:, the delegate methods tableView:willDeselectRowAtIndexPath: and tableView:didDeselectRowAtIndexPath: message are not sent.