rcCheckArea.right = CX_CHECKBOX;
if(!gSystemInfo.bScreenReader) rcCheckArea.right = CX_CHECKBOX;
void InvalidateLBCheckbox(HWND hwndListBox){  RECT rcCheckArea;  // retrieve the rectangle of all list items to update.  GetClientRect(hwndListBox, &rcCheckArea);  // set the right coordinate of the rectangle to be the same  // as the right edge of the bitmap drawn.  rcCheckArea.right = CX_CHECKBOX;  // It then invalidates the checkbox region to be redrawn.  // Invalidating the region sends a WM_DRAWITEM message to  // the dialog, which redraws the region given the  // node attirbute, in this case it is a bitmap of a  // checked/unchecked checkbox.  InvalidateRect(hwndListBox, &rcCheckArea, TRUE);}