Typically occurs when the value of the MaskedTextBox.Multiline property has changed; however, this event is not raised by System.Windows.Forms.MaskedTextBox.
The MaskedTextBox.MultilineChanged event is inherited from the base System.Windows.Forms.TextBoxBase class. However, because the System.Windows.Forms.MaskedTextBox control does not support multiline configuration, this event is not implemented in System.Windows.Forms.MaskedTextBox.