XAML ViewBox forces a bad rescale on ListBoxItem MouseOver

Question

I have the following XAML layout (ListBox where the Items are RadioButtons styled as ToggleButtons). The ListBox and the ToggleButton items scales and fills the ToggleButton items nicely to adapt to the window size. This is just as I want, but when I have the mouse over a ToggleButton in the ListBox, the style sets the Text to be bold. This is also what I want, but the problem is that it makes the button slightly bigger. When having the mouse over the ToggleButton item with the longest text the ViewBox refreshes and rescales all the ToggleButton controls. It looks like all the ToggleButtons makes a jump. How can I prevent such rescaling of the ToggleButtons still filling out the complete Grid Column and Row with the ListBox and its ToggleButton items?

 <Viewbox Stretch="UniformToFill" Grid.Row="1" Grid.Column="0" VerticalAlignment="Stretch" Margin="5,0,0,15">
            <Grid x:Name="LeftSide" Grid.Row="1" Grid.Column="0" VerticalAlignment="Stretch">
                <Grid.RowDefinitions>
                    <RowDefinition Height="1*"/>
                </Grid.RowDefinitions>
                <ListBox  Grid.Column="0" Grid.Row="0" Grid.RowSpan="10" ItemsSource="{Binding LeftPaneViewModelInfoItems, UpdateSourceTrigger=PropertyChanged}" Background="Transparent" SelectedItem="{Binding SelectedViewModelInfoItem}">
                    <ListBox.ItemContainerStyle>
                        <Style TargetType="{x:Type ListBoxItem}">
                            <Setter Property="Background" Value="Transparent" />
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="{x:Type ListBoxItem}">
                                        <ContentPresenter />
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </ListBox.ItemContainerStyle>
                    <ListBox.ItemTemplate>
                        <DataTemplate>
                            <RadioButton 
                                Content="{Binding Text}"                                     
                                GroupName="DisplayPage"
                                IsChecked="{Binding IsSelected, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ListBoxItem}}}"
                                Style="{StaticResource RadioButtonToggleButtonStyle}"                                     
                                >
                            </RadioButton>
                        </DataTemplate>
                    </ListBox.ItemTemplate>
                </ListBox>
            </Grid>
        </Viewbox>

Answer 1

Did not find a good solution. I ended up removing the bold setter property from the Mouse Over style.