selfImGuiListClipper handle on which this method operates.
item_indexZero-based item index to include or seek to, within the clipper item count.
Call ListClipper_IncludeItemByIndex(self, item_index) or ListClipper_IncludeItemsByIndex(self, item_begin, item_end) before the first ListClipper_Step(self) to include items regardless of visibility.
(Due to alignment / padding of certain items it is possible that an extra item may be included on either end of the display range).
Include an item in the list clipper output regardless of visibility.