Latest cursor position in viewport coords. Always present during a drag,
even when the cursor is outside every registered drop target. Used by
<DragProvider> to position the ghost overlay.
0-based prospective insertion index. Undefined when the strategy
gives no positional answer (e.g. splits) or when the target didn't
register a getInsertionIndex.
Latest cursor position in viewport coords. Always present during a drag, even when the cursor is outside every registered drop target. Used by
<DragProvider>to position the ghost overlay.