Use the SendMessage property to specify whether the control sends scroll messages to the parent window. If the SendMessage property is True, the control sends scroll bar related messages to the parent window of the control, when certain actions occurs in the control. For instance, if the user clicks the left button in an horizontal message, the control sends the WM_HSCROLL message with the code SB_LINELEFT. Use the SendMessage property only when you need to handle messages in your parent window. Use the Mode property to specify the control's orientation.