toggleActive method
void
toggleActive()
Implementation
void toggleActive() {
final v = _visibleOf(_activeMaster);
final r = v < 0 ? 0 : v;
if (_isRowMode) {
selectRowAt(r, additive: _isMulti);
} else if (_isCellMode) {
selectCellAt(r, _activeCol, additive: _isMulti);
}
}