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Customizing ScrollViewer Style breaks RichTextBox Mouse Wheel Scrolling

To reproduce this, simply add this style to any wpf project that has a RichTextBox:
https://pastebin.com/dJAqFC3d
And a full minimal project can be located here:
https://drive.google.com/file/d/1a7e-vwKpt1Emg7fhMhVRLccwrjOlhWk1/view?usp=sharing
Also an example of the two styles:
<!--
This style does NOT break RichTextBox Scrolling
-->
<Style TargetType="{x:Type ScrollViewer}">
<Style.Resources>
<SolidColorBrush x:Key="{x:Static SystemColors.ControlBrushKey}" Color="Transparent" />
</Style.Resources>
</Style>
<!--
The Style below breaks Rich Text Box
-->
<!--<Style TargetType="{x:Type ScrollViewer}">
<Setter Property="CanContentScroll" Value="True"></Setter>
<Setter Property="PanningMode" Value="Both"></Setter>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ScrollViewer}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<ScrollContentPresenter Grid.Column="0" />
<ScrollBar
x:Name="PART_VerticalScrollBar"
Grid.Row="0"
Grid.Column="1"
Maximum="{TemplateBinding ScrollableHeight}"
ViewportSize="{TemplateBinding ViewportHeight}"
Visibility="{TemplateBinding ComputedVerticalScrollBarVisibility}"
Value="{TemplateBinding VerticalOffset}" />
<ScrollBar
x:Name="PART_HorizontalScrollBar"
Grid.Row="1"
Grid.Column="0"
Maximum="{TemplateBinding ScrollableWidth}"
Orientation="Horizontal"
ViewportSize="{TemplateBinding ViewportWidth}"
Visibility="{TemplateBinding ComputedHorizontalScrollBarVisibility}"
Value="{TemplateBinding HorizontalOffset}" />
--><!--<Rectangle Grid.Row="1" Grid.Column="1" Fill="Red"/>--><!--
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>-->
Then at the bottom of the style, comment out either of the ScrollViewer styles to swap between them. One simply overrides the bottom right rectangle color. The other does the same, but also defines the scrollbars. The style that defines the scrollbars breaks vertical scrolling.
This can also be reproduced using the official Microsoft provided styles, located here:
https://learn.microsoft.com/en-us/dotnet/desktop/wpf/controls/scrollbar-styles-and-templates?view=netframeworkdesktop-4.8
and here
https://learn.microsoft.com/en-us/dotnet/desktop/wpf/controls/scrollviewer-styles-and-templates?view=netframeworkdesktop-4.8
UPDATE: (The above links will soon be an invalid example, because this issue has been submitted, and it is apparently going to be addressed and fixed)
Does anyone know why declaring a custom style for ScrollViewers breaks RichTextBox mouse wheel scrolling?
Edit: It should also be noted that the above example does not hinder or break the vertical mouse wheel scrolling of any other control (that I've noticed). RichTextBox seems to be an edge case.

Found the solution, and it's actually stupid easy.
You have to add CanContentScroll="True" to the ScrollContentPresenter within the ScrollViewer control template. Here is an example:
<Style TargetType="{x:Type ScrollViewer}">
<Setter Property="CanContentScroll" Value="True"></Setter>
<Setter Property="PanningMode" Value="Both"></Setter>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ScrollViewer}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<ScrollContentPresenter CanContentScroll="True" Grid.Column="0" />
<ScrollBar
x:Name="PART_VerticalScrollBar"
Grid.Row="0"
Grid.Column="1"
Maximum="{TemplateBinding ScrollableHeight}"
ViewportSize="{TemplateBinding ViewportHeight}"
Visibility="{TemplateBinding ComputedVerticalScrollBarVisibility}"
Value="{TemplateBinding VerticalOffset}" />
<ScrollBar
x:Name="PART_HorizontalScrollBar"
Grid.Row="1"
Grid.Column="0"
Maximum="{TemplateBinding ScrollableWidth}"
Orientation="Horizontal"
ViewportSize="{TemplateBinding ViewportWidth}"
Visibility="{TemplateBinding ComputedHorizontalScrollBarVisibility}"
Value="{TemplateBinding HorizontalOffset}" />
<Rectangle Grid.Row="1" Grid.Column="1" Fill="Red"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
This is not mentioned anywhere within the microsoft style example, and they also ommit it from their suggested style template.

change the backgorund of the pivot item in windows phone 8

I have a style
<Style x:Key="PivotStyle1" TargetType="phone:Pivot">
<Setter Property="Margin" Value="0"/>
<Setter Property="Padding" Value="0"/>
<Setter Property="Foreground" Value="{StaticResource PhoneForegroundBrush}"/>
<Setter Property="Background" Value="Transparent"/>
<Setter Property="ItemsPanel">
<Setter.Value>
<ItemsPanelTemplate>
<Grid/>
</ItemsPanelTemplate>
</Setter.Value>
</Setter>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="phone:Pivot">
<Grid HorizontalAlignment="{TemplateBinding HorizontalAlignment}" VerticalAlignment="{TemplateBinding VerticalAlignment}">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid Background="{TemplateBinding Background}" CacheMode="BitmapCache" Grid.RowSpan="3"/>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition />
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Image
Height="45"
HorizontalAlignment="Left"
Margin="12,0,0,0"
VerticalAlignment="Bottom"
Source="/Assets/Icons/MyTasks.png" />
<ContentControl
ContentTemplate="{TemplateBinding TitleTemplate}"
Content="{TemplateBinding Title}"
Grid.Column="1"
HorizontalAlignment="Left"
Margin="10,0,0,-7"
VerticalAlignment="Center"
Style="{StaticResource PivotTitleStyle}"/>
<Image
Grid.Column="2"
Height="55" Margin="0,10,20,0"
HorizontalAlignment="Right"
VerticalAlignment="Bottom"
Source="/Assets/Icons/Settings.png"/>
</Grid>
<Primitives:PivotHeadersControl x:Name="HeadersListElement" Grid.Row="1"/>
<ItemsPresenter x:Name="PivotItemPresenter" Margin="{TemplateBinding Padding}"
Grid.Row="2"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
This is my pivot code:
<phone:Pivot Title="MY TASKS" Style="{StaticResource PivotStyle1}" >
<!--Pivot item one-->
<phone:PivotItem Header="all">
</phone:PivotItem>
<phone:PivotItem Header="assigned">
</phone:PivotItem>
<phone:PivotItem Header="overdue">
</phone:PivotItem>
</phone:Pivot>
I want to change the color of pivot items. pivot item header "all" in red color, pivot item "assigned" in green color. I have tried to change the background, but that changes the full background. please suggest.

This one worked for me.
<phone:PivotItem>
<phone:PivotItem.Header>
<TextBlock Text="assigned" Foreground="#FF145377"></TextBlock>
</phone:PivotItem.Header>
</phone:PivotItem>

How to Change Pivot Header Template in Windows Phone 8

I would like to be able to change the background of the Pivot Headers and Application Title in Windows Phone 8. From what I gather, I must create a custom style targeting the Pivot control. I am not sure, however, to change the background of only the headers?
I would like to adjust the style somehow
<Style x:Key="MyPivotStyle" TargetType="phone:Pivot">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="phone:Pivot">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid CacheMode="BitmapCache" Grid.RowSpan="2">
<Grid.Background>
<ImageBrush ImageSource="/Assets/bg_header.png"/>
</Grid.Background>
</Grid>
<Grid Background="{TemplateBinding Background}" CacheMode="BitmapCache" Grid.Row="2" />
<ContentPresenter ContentTemplate="{TemplateBinding TitleTemplate}" Margin="24,17,0,-7">
<StackPanel Orientation="Horizontal">
<Image Source="/Assets/company_name.png" Width="213.75" HorizontalAlignment="Left" VerticalAlignment="Top" />
<Button HorizontalAlignment="Right" VerticalAlignment="Top" Margin="140,-20,0,35" BorderThickness="0" x:Name="btnHome">
<Image Source="/Assets/btnHome.png" Width="48" Height="48" ></Image>
</Button>
</StackPanel>
</ContentPresenter>
<controlsPrimitives:PivotHeadersControl x:Name="HeadersListElement" Foreground="White" Grid.Row="1"/>
<ItemsPresenter x:Name="PivotItemPresenter" Margin="{TemplateBinding Padding}" Grid.Row="2"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>

EDITED for WinRT (sorry for the delay and thanks for the reminder to update this answer):
To edit a full template right click on the control when in Document Outline and select Edit Template - Current (in Visual Studio or Blend) and the template will be generated for you and you can edit as you want, see my answer here for screenshots.
Here are the two examples below (posted in 2013) redone for Windows Phone Windows Runtime:
<Grid Background="Transparent">
<Pivot Title="Re-templating example">
<Pivot.HeaderTemplate>
<DataTemplate>
<Grid Background="Blue">
<TextBlock Text="{Binding}" />
</Grid>
</DataTemplate>
</Pivot.HeaderTemplate>
<Pivot.TitleTemplate>
<DataTemplate>
<Grid Background="Green">
<TextBlock Text="{Binding}" />
</Grid>
</DataTemplate>
</Pivot.TitleTemplate>
<PivotItem Header="One">
<TextBlock FontSize="35"
Text="This is item one" />
</PivotItem>
<PivotItem Header="Two">
<TextBlock FontSize="35"
Text="This is item 2" />
</PivotItem>
</Pivot>
</Grid>
And second example, notice that we are wrapping the ContentPresenter in a Grid (you could use a border as well or any other element):
<Page.Resources>
<SolidColorBrush x:Key="PivotBackground" Color="#FFE46C08"/>
<Style x:Key="PivotStyle" TargetType="Pivot">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Pivot">
<Grid x:Name="RootElement" HorizontalAlignment="{TemplateBinding HorizontalAlignment}" VerticalAlignment="{TemplateBinding VerticalAlignment}">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<!--Notice that ContentControl is wrapped in a Grid and Background set to resource furtehr up-->
<Grid VerticalAlignment="Center" Background="{StaticResource PivotBackground}">
<ContentControl x:Name="TitleContentControl" ContentTemplate="{TemplateBinding TitleTemplate}" Content="{TemplateBinding Title}" Style="{StaticResource PivotTitleContentControlStyle}"/>
</Grid>
<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">
<!--Background set to resource further up-->
<PivotHeaderPanel Background="{StaticResource PivotBackground}" 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>
</Page.Resources>
Using the above style:
<Grid Background="Transparent">
<Pivot Style="{StaticResource PivotStyle}"
Title="Re-templating example">
<PivotItem Header="One">
<TextBlock FontSize="35" Text="This is item one" />
</PivotItem>
<PivotItem Header="Two">
<TextBlock FontSize="35" Text="This is item 2"/>
</PivotItem>
</Pivot>
</Grid>
By the way, it's usually preferred to keep styles in a separate style file- I've only kept them on the same page for simplicity for this example. If you remove the x:key attribute the style will be applied to all the controls of the set target type (Pivot in this example).
Answer from 2013 for Windows Phone 7.X and Windows Phone 8 (WP Silverlight:
There are a few ways you can do it, but here is one example:
<Grid x:Name="LayoutRoot" Background="Transparent">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<phone:Pivot Grid.Row="1">
<phone:Pivot.HeaderTemplate>
<DataTemplate>
<Grid Background="Red" Height="200">
<TextBlock Text="{Binding}"/>
</Grid>
</DataTemplate>
</phone:Pivot.HeaderTemplate>
<phone:PivotItem Header="Test">
<TextBlock Text="ghjgb"/>
</phone:PivotItem>
<phone:PivotItem Header="Test">
<TextBlock Text="ghjgb"/>
</phone:PivotItem>
</phone:Pivot>
If you however want to do this:
You can do this, remove the x:key to apply to all pivoits, or use the key to set the style on just selected pivoit elements like so:
<controls:Pivot Title="The Marathon Runner" Style="{StaticResource PivotStyle}">
<Style x:Key="PivotStyle" TargetType="phone:Pivot">
<Setter Property="Margin" Value="0"/>
<Setter Property="Padding" Value="0"/>
<Setter Property="Foreground" Value="{StaticResource PhoneForegroundBrush}"/>
<Setter Property="Background" Value="Transparent"/>
<Setter Property="ItemsPanel">
<Setter.Value>
<ItemsPanelTemplate>
<Grid/>
</ItemsPanelTemplate>
</Setter.Value>
</Setter>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="phone:Pivot">
<Grid HorizontalAlignment="{TemplateBinding HorizontalAlignment}"
VerticalAlignment="{TemplateBinding VerticalAlignment}">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid Background="#ff9000" CacheMode="BitmapCache" Grid.RowSpan="2" />
<Grid Background="{TemplateBinding Background}" CacheMode="BitmapCache"
Grid.Row="2" />
<ContentPresenter ContentTemplate="{TemplateBinding TitleTemplate}"
Content="{TemplateBinding Title}" Margin="24,17,0,-7"/>
<Primitives:PivotHeadersControl x:Name="HeadersListElement"
Grid.Row="1"/>
<ItemsPresenter x:Name="PivotItemPresenter"
Margin="{TemplateBinding Padding}" Grid.Row="2"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
Dont forget to use:
xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
xmlns:Primitives="clr-namespace:Microsoft.Phone.Controls.Primitives;assembly=Microsoft.Phone"

Custom ScrollBar Thumb can't be dragged in DataGrid (but RepeatButtons work OK)?

I've tried customizing the look and feel of the ScrollBar of a DataGrid in WPF, simply by applying new style on the ScrollBar. This style changes the Template of the ScrollBar to a new one. Almost works fine except that I can't hold mouse down on the Thumb and drag to scroll, I just can click on the RepeatButtons (both Line buttons and Page buttons work OK) to scroll.
I'm still new to WPF, I don't know what the problem might be here. Here is the code:
<DataGrid HorizontalAlignment="Left" VerticalAlignment="Top" ItemsSource="{Binding}" SnapsToDevicePixels="True">
<DataGrid.Resources>
<Style TargetType="ScrollBar">
<Style.Resources>
<ControlTemplate x:Key="verRepeat" TargetType="RepeatButton">
<Border CornerRadius="4" BorderBrush="Green" BorderThickness="1" Background="Yellow">
<ContentPresenter Width="18" Height="18"/>
</Border>
</ControlTemplate>
<ControlTemplate x:Key="midRepeat" TargetType="RepeatButton">
<Border Background="Transparent">
<ContentPresenter/>
</Border>
</ControlTemplate>
<ControlTemplate x:Key="verScroll" TargetType="ScrollBar">
<Grid>
<Grid.RowDefinitions>
<RowDefinition MaxHeight="18"/>
<RowDefinition/>
<RowDefinition MaxHeight="18"/>
</Grid.RowDefinitions>
<Border Grid.RowSpan="3"/>
<RepeatButton Grid.Row="0" Width="18" Command="ScrollBar.LineUpCommand" Template="{StaticResource verRepeat}">
</RepeatButton>
<Track Grid.Row="1" IsDirectionReversed="True">
<Track.DecreaseRepeatButton>
<RepeatButton Command="ScrollBar.PageUpCommand" Template="{StaticResource midRepeat}">
</RepeatButton>
</Track.DecreaseRepeatButton>
<Track.Thumb>
<Thumb Margin="2,0,2,0">
<Thumb.Template>
<ControlTemplate TargetType="Thumb">
<Border Background="Green"/>
</ControlTemplate>
</Thumb.Template>
</Thumb>
</Track.Thumb>
<Track.IncreaseRepeatButton>
<RepeatButton Command="ScrollBar.PageDownCommand" Template="{StaticResource midRepeat}">
</RepeatButton>
</Track.IncreaseRepeatButton>
</Track>
<RepeatButton Grid.Row="2" Command="ScrollBar.LineDownCommand" Template="{StaticResource verRepeat}">
</RepeatButton>
</Grid>
</ControlTemplate>
<ControlTemplate x:Key="horScroll" TargetType="ScrollBar">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition MaxWidth="18"/>
<ColumnDefinition Width="0.00001*"/>
<ColumnDefinition MaxWidth="18"/>
</Grid.ColumnDefinitions>
<Border Grid.ColumnSpan="3"/>
<RepeatButton Grid.Column="0" Height="18" Command="ScrollBar.LineLeftCommand" Template="{StaticResource verRepeat}">
</RepeatButton>
<Track Grid.Column="1" IsDirectionReversed="False" Focusable="False">
<Track.DecreaseRepeatButton>
<RepeatButton Command="ScrollBar.PageLeftCommand" Template="{StaticResource midRepeat}">
</RepeatButton>
</Track.DecreaseRepeatButton>
<Track.Thumb>
<Thumb>
<Thumb.Template>
<ControlTemplate TargetType="Thumb">
<Grid>
<Border Background="Green" Margin="0,1,0,1"/>
<ContentPresenter Width="18" Height="18"/>
</Grid>
</ControlTemplate>
</Thumb.Template>
</Thumb>
</Track.Thumb>
<Track.IncreaseRepeatButton>
<RepeatButton Command="ScrollBar.PageRightCommand" Template="{StaticResource midRepeat}">
</RepeatButton>
</Track.IncreaseRepeatButton>
</Track>
<RepeatButton Grid.Column="2" Command="ScrollBar.LineRightCommand" Template="{StaticResource verRepeat}">
</RepeatButton>
</Grid>
</ControlTemplate>
</Style.Resources>
<Setter Property="OverridesDefaultStyle" Value="True"/>
<Style.Triggers>
<Trigger Property="Orientation" Value="Horizontal">
<Setter Property="Template" Value="{StaticResource horScroll}"/>
</Trigger>
<Trigger Property="Orientation" Value="Vertical">
<Setter Property="Template" Value="{StaticResource verScroll}"/>
</Trigger>
</Style.Triggers>
</Style>
</DataGrid.Resources>
</DataGrid>
I think I miss something here, the Thumb seems to be unable to interact with.
Here is the screenshot of the grid:

All is fine, just to Track to add the name of PART_Track as follows:
<Track x:Name="PART_Track" Grid.Row="1" IsDirectionReversed="True" ... />
Without this Thumb does not work.
Note: When designing your template and style better look at the original, at least in order to know the names of the pattern.
Here is a little description about the importance parts of the Template.

Black background of WPF Window

I created simple window and applied style to it. Now, when I run application background is black:
In XAML it looks normal:
What is causing this?
Here is XAML code:
<Window SizeToContent="WidthAndHeight"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
x:Class="WPFTest.MainWindow">
<Window.Style>
<Style TargetType="Window">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="Window">
<Grid Name="LayoutRoot" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid Grid.Row="0">
<ContentPresenter />
</Grid>
<StatusBar Name="statusBar1" Height="23" HorizontalAlignment="Stretch" VerticalAlignment="Top" Grid.Row="1" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Window.Style>
<Grid>
<Grid Height="114" HorizontalAlignment="Center" Margin="1,0,557,622" Name="grid" VerticalAlignment="Bottom" Width="466">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="100*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="25*" />
<RowDefinition Height="25*" />
<RowDefinition Height="25*" />
<RowDefinition Height="25*" />
</Grid.RowDefinitions>
<Label Content="Label4" Grid.Column="0" Grid.Row="3" HorizontalAlignment="Left" Margin="3,0,3,0" MinHeight="16" MinWidth="97" Name="xResourceLabel4" VerticalAlignment="Bottom" />
<Label Content="Label1" Grid.Column="0" Grid.Row="0" HorizontalAlignment="Left" Margin="3,0,3,0" MinHeight="16" MinWidth="98" Name="xResourceLabel1" VerticalAlignment="Bottom" />
<Label Content="Label2" Grid.Column="0" Grid.Row="1" HorizontalAlignment="Left" Margin="3,0,3,0" MinHeight="16" MinWidth="114" Name="xResourceLabel2" VerticalAlignment="Bottom" />
<Label Content="Label3" Grid.Column="0" Grid.Row="2" HorizontalAlignment="Left" Margin="3,0,3,0" MinHeight="16" MinWidth="80" Name="xResourceLabel3" VerticalAlignment="Bottom" />
<TextBox Background="#FFFFFF99" Grid.ColumnSpan="2" HorizontalAlignment="Center" Margin="120,0,189,0" MinHeight="23" MinWidth="157" Name="tbREGNR" VerticalAlignment="Bottom" />
<TextBox Background="#FFFFFF99" Grid.Column="1" Grid.Row="1" HorizontalAlignment="Center" Margin="0,0,189,0" MinHeight="23" MinWidth="157" Name="tbFaFabnr" VerticalAlignment="Bottom" />
<ComboBox Background="#FFFFFF99" DisplayMemberPath="" Grid.Column="1" Grid.Row="2" HorizontalAlignment="Center" Margin="0,0,189,0" MinHeight="24" MinWidth="157" Name="cb" SelectedValuePath="" VerticalAlignment="Bottom" />
<TextBox Background="#FFFF99CC" Grid.Column="1" Grid.Row="3" HorizontalAlignment="Center" Margin="0,0,175,0" MinHeight="23" MinWidth="171" Name="tbComp" VerticalAlignment="Bottom" />
</Grid>
</Grid>
</Window>

<Grid Name="LayoutRoot" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Background="White">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid Grid.Row="0">
<ContentPresenter />
</Grid>
<StatusBar Name="statusBar1" Height="23" HorizontalAlignment="Stretch" VerticalAlignment="Top" Grid.Row="1" />
</Grid>
Because you are overriding the default template for the Window you are taking away the style effects (of which one is background = black on the root grid)
see above, i've put it in the template and it should now work (Background="White")
Below is the default template for a window (Taken From Blend)
<ControlTemplate x:Key="WindowTemplateKey" TargetType="{x:Type Window}">
<Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}">
<Grid>
<AdornerDecorator>
<ContentPresenter/>
</AdornerDecorator>
<ResizeGrip x:Name="WindowResizeGrip" HorizontalAlignment="Right" IsTabStop="false" Visibility="Collapsed" VerticalAlignment="Bottom"/>
</Grid>
</Border>
<ControlTemplate.Triggers>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="ResizeMode" Value="CanResizeWithGrip"/>
<Condition Property="WindowState" Value="Normal"/>
</MultiTrigger.Conditions>
<Setter Property="Visibility" TargetName="WindowResizeGrip" Value="Visible"/>
</MultiTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
<Style x:Key="WindowStyle1" TargetType="{x:Type Window}">
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}"/>
<Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.WindowBrushKey}}"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Window}">
<Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}">
<AdornerDecorator>
<ContentPresenter/>
</AdornerDecorator>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="ResizeMode" Value="CanResizeWithGrip">
<Setter Property="Template" Value="{StaticResource WindowTemplateKey}"/>
</Trigger>
</Style.Triggers>
</Style>

Based on TBohnen.jnr's answer, the actual correct answer would be do it as the default window template and add Background="{TemplateBinding Background}" to the top-level child element of the ControlTemplate. In the default template it is a Border, whereas in your case it's the Grid:
<Grid Background="{TemplateBinding Background}" Name="LayoutRoot" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">