Changing RequestedTheme from C# affects Pivot Margins

Question

This is a universal app.
I created a style for PivotItem and Pivot that set Margin and Padding to 0.
I've setup a dark and light theme.
I can change the RequestedTheme to either in App.xaml and it works fine.
If I change the RequestedTheme of the App's Root frame during run time, the margin and padding of the pivot are reset.
The left image is how it should look, the right image is how it looks after changing theme at runtime.
switch(App.AppDataSerializer.AppData.Config.SelectedApplicationTheme)
case 0:
default:
App.RootFrame.RequestedTheme = Windows.UI.Xaml.ElementTheme.Light;
break;
case 1:
App.RootFrame.RequestedTheme = Windows.UI.Xaml.ElementTheme.Dark;
break;
<Style
x:Key="PivotItemNoMarginStyle"
TargetType="PivotItem">
<Setter
Property="Background"
Value="Red" />
<Setter
Property="Margin"
Value="0" />
<Setter
Property="Padding"
Value="0" />
<Setter
Property="HorizontalContentAlignment"
Value="Stretch" />
<Setter
Property="VerticalContentAlignment"
Value="Stretch" />
<Setter
Property="Template">
<Setter.Value>
<ControlTemplate
TargetType="PivotItem">
<Grid
Background="{TemplateBinding Background}"
HorizontalAlignment="{TemplateBinding HorizontalAlignment}"
VerticalAlignment="{TemplateBinding VerticalAlignment}">
<VisualStateManager.VisualStateGroups>
<VisualStateGroup
x:Name="Pivot">
<VisualState
x:Name="Right" />
<VisualState
x:Name="Left" />
<VisualState
x:Name="Center" />
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<ContentPresenter
ContentTemplate="{TemplateBinding ContentTemplate}"
Content="{TemplateBinding Content}"
HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
Margin="0"
VerticalAlignment="{TemplateBinding VerticalContentAlignment}" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style
x:Key="PivotNoMarginStyle"
TargetType="Pivot">
<Setter
Property="Margin"
Value="0" />
<Setter
Property="Padding"
Value="0" />
<Setter
Property="Foreground"
Value="{ThemeResource PhoneForegroundBrush}" />
<Setter
Property="Background"
Value="Blue" />
<Setter
Property="ItemsPanel">
<Setter.Value>
<ItemsPanelTemplate>
<Grid />
</ItemsPanelTemplate>
</Setter.Value>
</Setter>
<Setter
Property="Template">
<Setter.Value>
<ControlTemplate
TargetType="Pivot">
<Grid
x:Name="RootElement"
Background="{TemplateBinding Background}"
HorizontalAlignment="{TemplateBinding HorizontalAlignment}"
VerticalAlignment="{TemplateBinding VerticalAlignment}">
<Grid.RowDefinitions>
<RowDefinition
Height="Auto" />
<RowDefinition
Height="*" />
</Grid.RowDefinitions>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup
x:Name="Orientation">
<VisualState
x:Name="Portrait">
<Storyboard>
<ObjectAnimationUsingKeyFrames
Storyboard.TargetProperty="Margin"
Storyboard.TargetName="TitleContentControl">
<DiscreteObjectKeyFrame
KeyTime="0"
Value="{ThemeResource MyPivotPortraitThemePadding}" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState
x:Name="Landscape">
<Storyboard>
<ObjectAnimationUsingKeyFrames
Storyboard.TargetProperty="Margin"
Storyboard.TargetName="TitleContentControl">
<DiscreteObjectKeyFrame
KeyTime="0"
Value="{ThemeResource MyPivotLandscapeThemePadding}" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<ContentControl
x:Name="TitleContentControl"
ContentTemplate="{TemplateBinding TitleTemplate}"
Content="{TemplateBinding Title}"
Style="{StaticResource PivotTitleContentControlStyle}" />
<ScrollViewer
x:Name="ScrollViewer"
HorizontalSnapPointsAlignment="Center"
HorizontalSnapPointsType="MandatorySingle"
HorizontalScrollBarVisibility="Hidden"
Margin="{TemplateBinding Padding}"
Grid.Row="1"
Template="{StaticResource ScrollViewerScrollBarlessTemplate}"
VerticalSnapPointsType="None"
VerticalScrollBarVisibility="Disabled"
VerticalScrollMode="Disabled"
VerticalContentAlignment="Stretch"
ZoomMode="Disabled">
<PivotPanel
x:Name="Panel"
VerticalAlignment="Stretch">
<PivotHeaderPanel
x:Name="Header">
<PivotHeaderPanel.RenderTransform>
<CompositeTransform
x:Name="HeaderTranslateTransform"
TranslateX="0" />
</PivotHeaderPanel.RenderTransform>
</PivotHeaderPanel>
<ItemsPresenter
x:Name="PivotItemPresenter">
<ItemsPresenter.RenderTransform>
<TranslateTransform
x:Name="ItemsPresenterTranslateTransform"
X="0" />
</ItemsPresenter.RenderTransform>
</ItemsPresenter>
</PivotPanel>
</ScrollViewer>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>

Answer 1

The solution I came up with was to run this function in the Page.Loaded event handlers for each page with a Pivot
public static void ResetPivotItemMargins(DependencyObject obj)
var pivots = Zorn.Universal.VisualTreeUtil.FindElementsOfType<Pivot>(obj);
if (pivots.Any())
var pivotItems = pivots.First().Items;
foreach (PivotItem pivotItem in pivotItems)
pivotItem.Margin = new Thickness(0, 0, 0, 0);
public static List<T> FindElementsOfType<T>(DependencyObject parentElement) where T : DependencyObject
List<T> items = new List<T>();
var count = VisualTreeHelper.GetChildrenCount(parentElement);
if (count == 0)
return items;
for (int i = 0; i < count; i++)
var child = VisualTreeHelper.GetChild(parentElement, i);
if (child != null && child is T)
items.Add((T)child);
var result = FindElementsOfType<T>(child);
if (result.Count > 0)
items.AddRange(result);
return items;