selectActive method
Re-apply the selection at the cursor cell — keyboard nav uses this so the
highlight follows the active cell (range extends from the anchor).
Implementation
void selectActive({bool additive = false, bool range = false}) {
if (selectionIsRowMode) {
selectRow(_sel.row, additive: additive, range: range);
} else if (selectionIsCellMode) {
selectCell(_sel.row, _sel.col, additive: additive, range: range);
}
}