WPToolkit ListPicker not working

Question

I have databound toolkit:ListPicker in my windows phone application

 <StackPanel>
                <toolkit:ListPicker x:Name="MyListPicker"
                                    ItemsSource="{Binding AllLists}"
                                    HorizontalAlignment="Left"
                                    Margin="40,25,0,0"
                                    VerticalAlignment="Top">

                    <toolkit:ListPicker.ItemTemplate>
                        <DataTemplate>
                            <toolkit:ListPickerItem Content="{Binding ListName}" />
                        </DataTemplate>
                    </toolkit:ListPicker.ItemTemplate>
                </toolkit:ListPicker>
            </StackPanel>

and it works fine, until i add listbox

        <StackPanel>
            <ListBox x:Name="MyListBox"
                     Height="418"
                     Margin="10,107,0,0"
                     VerticalAlignment="Top"
                     Width="416">
                <StackPanel>
                    <TextBlock Text="Test 123">

                    </TextBlock>
                </StackPanel>
            </ListBox>
        </StackPanel>

After listbox is added to page, i'm unable to change selection of listpicker. I can open it and see all items that should be inside, but whatever i select, selection always remains same, first item in list.

Can someone help me with this?