selectAll method
void
selectAll()
Do nothing if mode is SelectionMode.single.
When mode is SelectionMode.sameGroup, this method will only work when there is only 1 group exists. If there is more than 1 groups, this method will do nothing.
Implementation
void selectAll() {
if (mode == SelectionMode.single) return;
if (mode == SelectionMode.sameGroup && groups.length > 1) return;
_selected = Set.from(_options.keys);
}