When a value greater than zero is entered into the control, a
nonvisible margin is placed in the control at the specified number of
pixels from the left side of the control. Any text that is entered that
extends beyond this margin is placed on the next line of text in the
control. This property affects all text currently entered into the
control as well as any additional text entered into the control after
the property is set. You can use this property to specify a maximum
line width for all text entered into a RichTextBox control.
