ToggleButton does not fill the area(windows phone)

Question

When I create ToggleButton it does not fill all area in grid. I think it's because the pressing area is more than viewable area of the button. How can I make these areas equal?

    <Grid Grid.Column="0">
        <ToggleButton x:Name="ToggleHorizontal"
                      IsChecked="False"/>

    </Grid>

Answer 1

By default toggle button (not only but it too) has touch area around visible border with thickness of 12 px (PhoneTouchTargetOverhang constant, see MSDN). You can see this by editing the style of toggle button in the Blend.
So you can set value of margin in your XAML to -12:

<Grid Grid.Column="0">
    <ToggleButton x:Name="ToggleHorizontal" Margin="-12"
                  IsChecked="False"/>

</Grid>

Or you can change this constant to 0 in toggle-button style.
Margin="{StaticResource PhoneTouchTargetOverhang}"
to
Margin="0"

Hope I correctly understood your question and my answer will be helpful

UPD: I think it's easier to set Margin value directly to your toggle button, but if you wish...
Add this to your resource section in page and don't forget to set style to your toggle button:

<phone:PhoneApplicationPage.Resources>
    <Style x:Key="PhoneButtonBase" TargetType="ButtonBase">
        <Setter Property="Background" Value="Transparent"/>
        <Setter Property="BorderBrush" Value="{StaticResource PhoneForegroundBrush}"/>
        <Setter Property="Foreground" Value="{StaticResource PhoneForegroundBrush}"/>
        <Setter Property="BorderThickness" Value="{StaticResource PhoneBorderThickness}"/>
        <Setter Property="FontFamily" Value="{StaticResource PhoneFontFamilySemiBold}"/>
        <Setter Property="FontSize" Value="{StaticResource PhoneFontSizeMediumLarge}"/>
        <Setter Property="Padding" Value="10,3,10,5"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="ButtonBase">
                    <Grid Background="Transparent">
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="CommonStates">
                                <VisualState x:Name="Normal"/>
                                <VisualState x:Name="MouseOver"/>
                                <VisualState x:Name="Pressed">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentContainer">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneBackgroundBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="ButtonBackground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneForegroundBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="ButtonBackground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneForegroundBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Disabled">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentContainer">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneDisabledBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="ButtonBackground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneDisabledBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="ButtonBackground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="Transparent"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                        <Border x:Name="ButtonBackground" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" CornerRadius="0" Margin="{StaticResource PhoneTouchTargetOverhang}">
                            <ContentControl x:Name="ContentContainer" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" Foreground="{TemplateBinding Foreground}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
                        </Border>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <Style x:Key="ToggleButtonStyle" BasedOn="{StaticResource PhoneButtonBase}" TargetType="ToggleButton">
        <Setter Property="Padding" Value="8"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="ToggleButton">
                    <Grid Background="Transparent">
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="CommonStates">
                                <VisualState x:Name="Normal"/>
                                <VisualState x:Name="Disabled">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="EnabledBackground">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Collapsed</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="DisabledBackground">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Visible</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                            <VisualStateGroup x:Name="CheckStates">
                                <VisualState x:Name="Unchecked"/>
                                <VisualState x:Name="Checked">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="EnabledBackground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneForegroundBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="EnabledBackground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneForegroundBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="EnabledContent">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneBackgroundBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="DisabledBackground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneDisabledBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="DisabledBackground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneDisabledBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="DisabledContent">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneBackgroundBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                        <Border x:Name="EnabledBackground" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Margin="0">
                            <ContentControl x:Name="EnabledContent" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" Foreground="{TemplateBinding Foreground}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
                        </Border>
                        <Border x:Name="DisabledBackground" BorderBrush="{StaticResource PhoneDisabledBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="Transparent" IsHitTestVisible="False" Margin="0" Visibility="Collapsed">
                            <ContentControl x:Name="DisabledContent" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" Foreground="{StaticResource PhoneDisabledBrush}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
                        </Border>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</phone:PhoneApplicationPage.Resources>

And your ToggleButton now:

<Grid Grid.Column="0">
    <ToggleButton x:Name="ToggleHorizontal" Margin="-12" Style="{StaticResource ToggleButtonStyle}"
                  IsChecked="False"/>

</Grid