You could always add code in the OnPaint event. If you just want to draw a single rectangle just declare a rectangle on the form object, then using mouse events once it is selected set the Selection Rectangle object to the appropriate values and then call this.Invalidate(); It will force a repaint of the object. Inside the paint routine you can have code to only bother drawing the rectangle if a selection has been made. The actual drawing of the rectangle can be done via the System.Windows.Forms.PaintEventArgs object which is passed to the routine. Simply use the e.Graphics.DrawRectangle(); method to draw the actual rectangle. An example of this called would be: e.Graphics.DrawRectangle(new Pen(Color.Red, 1), x, y, mySelection.Width, mySelection.Height); I am sure there is a better way out there but this should work.
