Created Unassigned: Checkboxes not checked when setting SelectedValue using MVVM [20203]

I wanted to use a "All" item in the list.
When selecting my item "All", I set the SelectedValue property to every possible value ...

```
private string _selected;
public string Selected
{
get { return _selected; }
set
{
if (value.Contains(Constants.CRITERIA_ALL))
{
var cs = string.Join(",", MyArrayOfValues);
Set(() => Selected, ref _selected, cs);
return;
}

Set(() => Selected, ref _selected, value);
}
}
```

The checkboxes are not checked ...