Binding of a check box doesn't transport the values to the model

I've created a list of check boxes and bound them as shown below.

<ListBox ItemsSource="{Binding AllCarrierTypes}">
  <ListBox.ItemTemplate>
    <DataTemplate>
      <CheckBox Content="{Binding Name}"
                IsChecked="{Binding Active,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                Checked="ToggleButton_OnChecked"
                Unchecked="ToggleButton_OnUnchecked"/>
    </DataTemplate>
  </ListBox.ItemTemplate>
</ListBox>

However, when I breakpoint on the unchecked event and see the contents of AllCarrierTypes, using Where() to only get the actives, I see that the list stays the same, despite the fact that those small thingies in the GUI actually are on and off. What can I do to troubleshoot it? According to the things I've read and seen, it supposed to work, so it's likely something stupid I've forgotten...