An application sends an LB_SETCARETINDEX message to set the focus rectangle to the item at the specified index in a multiple-selection list box. If the item is not visible, it is scrolled into view.
LB_SETCARETINDEX wParam = (WPARAM) index; // item index lParam = MAKELPARAM(fScroll, 0); // flag for scrolling item
Windows 95: The wParam parameter is limited to 16-bit values.
This means list boxes cannot contain more than 32,767 items. Although the
number of items is restricted, the total size in bytes of the items in a
listbox is limited only by available memory.
If an error occurs, the return value is LB_ERR.