Removes a rectangle from the current update region of the specified window
#include <WinAPIGdi.au3>
_WinAPI_ValidateRect ( $hWnd [, $tRECT = 0] )
| $hWnd | Handle to the window whose update region is to be modified. If this parameter is 0, the system invalidates and redraws all windows and sends the WM_ERASEBKGND and WM_NCPAINT messages to the window procedure before the function returns. |
| $tRECT | [optional] $tagRECT structure that contains the client coordinates of the rectangle to be removed from the update region. If this parameter is 0 (Default), the entire client area is removed. |
| Success: | True |
| Failure: | False |
Search ValidateRect in MSDN Library.