These are the EventArgs for the ContentsResized event, raised by the RichTextBox class when a contained element is resized. It allows you to retrieve the NewRectangle for the contents. public class ContentsResizedEventArgs : EventArgs { // Public Constructors public ContentsResizedEventArgs (System.Drawing.Rectangle newRectangle ); // Public Instance Properties public Rectangle NewRectangle {get; } } HierarchySystem.Object System.EventArgs ContentsResizedEventArgs Passed ToContentsResizedEventHandler.{BeginInvoke() , Invoke()} , RichTextBox.OnContentsResized() |