We Keep Coding

Make multi line design of tag control

I have applied the evernote tag control which is working but the design is not in multi line as I add tag it is added next to the previous tag and adding in the single line, but it has to move down when there is no more space on the page. Here is the screenshot of what I want:
I have followed this link : http://stackoverflow.com/questions/15167809/how-can-i-create-a-tagging-control-similar-to-evernote-in-wpf but still unable to get the tags in multi line. Please let me know where I am going wrong. Following is my xaml:
<!-- EvernoteTagControl default style -->
<Style TargetType="{x:Type local:EvernoteTagControl}">
<Style.Resources>
<SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="White"/>
<SolidColorBrush x:Key="{x:Static SystemColors.ControlBrushKey}" Color="White" />
<LinearGradientBrush x:Key="IconBrush" EndPoint="0,1">
<GradientStop Color="#5890f0" Offset="0" />
<GradientStop Color="#0351d7" Offset="1" />
</LinearGradientBrush>
</Style.Resources>
<Setter Property="FocusVisualStyle" Value="{x:Null}" />
<Setter Property="VerticalAlignment" Value="Top" />
<Setter Property="Margin" Value="15 25 15 15" />
<Setter Property="MinHeight" Value="25" />
<Setter Property="VerticalContentAlignment" Value="Center" />
<Setter Property="SnapsToDevicePixels" Value="True" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:EvernoteTagControl}">
<Grid>
<Grid.ColumnDefinitions>
<!--<ColumnDefinition Width="Auto" />-->
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<!--<Path Grid.Column="0" Margin="2" Fill="{StaticResource IconBrush}" Height="19" Stretch="Uniform" Data="M 50.535714,0.44196425 0.00446427,34.754464 l 0,106.906246 100.71874573,0 0,-107.124996 L 50.535714,0.44196425 z m 0.1875,21.21874975 c 6.311826,0 11.40625,5.094424 11.40625,11.40625 0,6.311826 -5.094424,11.4375 -11.40625,11.4375 -6.311826,0 -11.4375,-5.125674 -11.4375,-11.4375 0,-6.311826 5.125674,-11.40625 11.4375,-11.40625 z" />-->
<ItemsPresenter Grid.Column="0" Margin="2" />
<Button Margin="5,0,0,0" Grid.Column="1" Content="Click to add..." x:Name="PART_CreateTagButton">
<Button.Template>
<ControlTemplate TargetType="Button">
<ContentPresenter TextElement.Foreground="#FF555555" VerticalAlignment="Center" />
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Cursor" Value="Hand" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Button.Template>
</Button>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsEditing" Value="True">
<Setter TargetName="PART_CreateTagButton" Property="Visibility" Value="Collapsed" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
<Setter Property="ItemContainerStyle">
<Setter.Value>
<Style TargetType="{x:Type ListBoxItem}">
<Setter Property="FocusVisualStyle" Value="{x:Null}" />
</Style>
</Setter.Value>
</Setter>
<Setter Property="ItemsPanel" >
<Setter.Value>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal" />
</ItemsPanelTemplate>
</Setter.Value>
</Setter>
</Style>
<!-- EvernoteTagItem default style -->
<Style TargetType="{x:Type local:EvernoteTagItem}">
<Setter Property="FocusVisualStyle" Value="{x:Null}" />
<Setter Property="MinWidth" Value="50" />
<Setter Property="Margin" Value="0,0,2,0" />
<Setter Property="Padding" Value="5,2,0,2" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:EvernoteTagItem}">
<Button x:Name="PART_TagButton" Content="{TemplateBinding Text}" Foreground="#ffffff" Margin="{TemplateBinding Margin}" Padding="{TemplateBinding Padding}">
<Button.Template>
<ControlTemplate TargetType="Button">
<Border Margin="{TemplateBinding Margin}" Padding="{TemplateBinding Padding}" BorderBrush="#00698C" BorderThickness="1" CornerRadius="2" Background="#00698C" >
<Grid >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<ContentPresenter VerticalAlignment="Center" HorizontalAlignment="Left" Margin="0,0,0,2" />
<Button x:Name="PART_DeleteTagButton" Grid.Column="1" Margin="3,0" VerticalAlignment="Center" HorizontalAlignment="Right" >
<Button.Template>
<ControlTemplate>
<Grid Height="10" Width="10" Background="#00698C" >
<Path Stretch="Uniform" ClipToBounds="True" Stroke="{StaticResource HighlightBrush}" StrokeThickness="1" Data="M 85.364473,6.9977109 6.0640998,86.29808 6.5333398,85.76586 M 6.9926698,7.4977169 86.293043,86.79809 85.760823,86.32885" />
</Grid>
</ControlTemplate>
</Button.Template>
</Button>
</Grid>
</Border>
<!--<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Foreground" Value="#ffffff" />
<Setter TargetName="PART_DeleteTagButton" Property="Visibility" Value="Visible" />
</Trigger>
</ControlTemplate.Triggers>-->
</ControlTemplate>
</Button.Template>
</Button>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="IsEditing" Value="True">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:EvernoteTagItem}">
<tkInput:AutoCompleteBox x:Name="PART_InputBox"
Text="{Binding Text, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
ItemsSource="{Binding AllTags, RelativeSource={RelativeSource AncestorType={x:Type local:EvernoteTagControl}}}"
IsTextCompletionEnabled="True"
/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
I am getting these tags as:

Currently, you use a StackPanel as ItemsPanel, but a stack panel will never wrap its items in multiple dimensions. So instead, you should try panels like WrapPanel or UniformGrid
For the WrapPanel, you also need to set a Width in the ItemContainerStyle in order to assure same size for all tag items (according to your "what I want" picture).
Then you have to decide on the positioning of your PART_CreateTagButton button. With multi lines of tags, the grid layout of ItemsPresenter and PART_CreateTagButton might no longer be appropriate.
You can probably create a compound items source of the original tag items source and the button as last item. This way, the button will always be properly aligned with the tags. See Add extra items when using ItemsSource and How do you bind a CollectionContainer to a collection in a view model? for more details.

HorizontalAlignment="Stretch" not working in TreeViewItem

Here's an example where it is not working:
<Window x:Class="WpfApplication2.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApplication2"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<TreeView HorizontalAlignment="Stretch">
<TreeViewItem Header="Stuff" HorizontalAlignment="Stretch" HorizontalContentAlignment="Stretch">
<Grid HorizontalAlignment="Stretch">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Label Grid.Column="0">Some random text</Label>
<TextBox Grid.Column="1"></TextBox>
</Grid>
</TreeViewItem>
</TreeView>
</Window>
I want the text box to stretch to the width of the window, but instead you get this:
The textbox expands as you type, which is not what I want.
I am thinking now it might be possible to set a binding on the width of the 2nd column to the width of the TreeViewItem but I'm not sure how to do that.
I've tried putting the grid in assorted panels, but that doesn't work either. I have also set the HorizontalAlignment and HorizontalContentAlignment to Stretch on the textbox itself, but that also doesn't work.
Is this some limitation of the Grid control? Putting a textbox in a tree view by itself will make it expand as I want, but I need the label to be next to it and if there are multiple fields it looks MUCH better if all the textboxes are aligned.
UPDATE
Using a different ControlTemplate allows headers to stretch but contents still don't stretch.
<TreeView HorizontalAlignment="Stretch">
<TreeViewItem Style="{DynamicResource StretchableTreeViewItemTemplate}" HorizontalAlignment="Stretch" Header="Stuff">
<Grid HorizontalAlignment="Stretch">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Label Grid.Column="0">Some random text</Label>
<TextBox Grid.Column="1" HorizontalAlignment="Stretch"></TextBox>
</Grid>
</TreeViewItem>
</TreeView>
<Style x:Key="StretchableTreeViewItemTemplate" TargetType="TreeViewItem"
BasedOn="{StaticResource {x:Type TreeViewItem}}">
<Setter Property="HorizontalContentAlignment"
Value="Center" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="TreeViewItem">
<StackPanel>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"
MinWidth="19" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition />
</Grid.RowDefinitions>
<!--
Note that the following do not work, but I believe the top 2 should?!
<ToggleButton IsChecked="{TemplateBinding IsExpanded}" ClickMode="Press" Name="Expander">
<ToggleButton IsChecked="{TemplateBinding Property=IsExpanded}" ClickMode="Press" Name="Expander">
<ToggleButton IsChecked="{TemplateBinding Path=IsExpanded}" ClickMode="Press" Name="Expander">
-->
<ToggleButton IsChecked="{Binding Path=IsExpanded, RelativeSource={RelativeSource TemplatedParent}}"
ClickMode="Press"
Name="Expander">
<ToggleButton.Style>
<Style TargetType="ToggleButton">
<Setter Property="UIElement.Focusable"
Value="false" />
<Setter Property="FrameworkElement.Width"
Value="16" />
<Setter Property="FrameworkElement.Height"
Value="16" />
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="ToggleButton">
<Border Padding="5,5,5,5"
Background="#00FFFFFF"
Width="16"
Height="16">
<Path Fill="#00FFFFFF"
Stroke="#FF989898"
Name="ExpandPath">
<Path.Data>
<PathGeometry Figures="M0,0L0,6L6,0z" />
</Path.Data>
<Path.RenderTransform>
<RotateTransform Angle="135"
CenterX="3"
CenterY="3" />
</Path.RenderTransform>
</Path>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="UIElement.IsMouseOver"
Value="True">
<Setter TargetName="ExpandPath"
Property="Shape.Stroke"
Value="#FF1BBBFA" />
<Setter TargetName="ExpandPath"
Property="Shape.Fill"
Value="#00FFFFFF" />
</Trigger>
<Trigger Property="ToggleButton.IsChecked"
Value="True">
<Setter TargetName="ExpandPath"
Property="UIElement.RenderTransform">
<Setter.Value>
<RotateTransform Angle="180"
CenterX="3"
CenterY="3" />
</Setter.Value>
</Setter>
<Setter TargetName="ExpandPath"
Property="Shape.Fill"
Value="#FF595959" />
<Setter TargetName="ExpandPath"
Property="Shape.Stroke"
Value="#FF262626" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ToggleButton.Style>
</ToggleButton>
<Border x:Name="Bd"
HorizontalAlignment="Stretch"
BorderThickness="{TemplateBinding Border.BorderThickness}"
BorderBrush="{TemplateBinding Border.BorderBrush}"
Padding="{TemplateBinding Control.Padding}"
Background="{TemplateBinding Panel.Background}"
SnapsToDevicePixels="True"
Grid.Column="1">
<ContentPresenter x:Name="PART_Header"
Content="{TemplateBinding HeaderedContentControl.Header}"
ContentTemplate="{TemplateBinding HeaderedContentControl.HeaderTemplate}"
ContentStringFormat="{TemplateBinding HeaderedItemsControl.HeaderStringFormat}"
ContentTemplateSelector="{TemplateBinding HeaderedItemsControl.HeaderTemplateSelector}"
ContentSource="Header"
HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}"
SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" />
</Border>
<ItemsPresenter x:Name="ItemsHost"
Grid.Column="1"
Grid.Row="1" />
</Grid>
</StackPanel>
<ControlTemplate.Triggers>
<Trigger Property="TreeViewItem.IsExpanded"
Value="False">
<Setter TargetName="ItemsHost"
Property="UIElement.Visibility"
Value="Collapsed" />
</Trigger>
<Trigger Property="ItemsControl.HasItems"
Value="False">
<Setter TargetName="Expander"
Property="UIElement.Visibility"
Value="Hidden" />
</Trigger>
<Trigger Property="TreeViewItem.IsSelected"
Value="True">
<Setter TargetName="Bd"
Property="Panel.Background"
Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}" />
<Setter Property="TextElement.Foreground"
Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}" />
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="TreeViewItem.IsSelected"
Value="True" />
<Condition Property="Selector.IsSelectionActive"
Value="False" />
</MultiTrigger.Conditions>
<Setter TargetName="Bd"
Property="Panel.Background"
Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" />
<Setter Property="TextElement.Foreground"
Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" />
</MultiTrigger>
<Trigger Property="UIElement.IsEnabled"
Value="False">
<Setter Property="TextElement.Foreground"
Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
Results:
Trying with Pikoh's solution:
<local:StretchingTreeView HorizontalAlignment="Stretch">
<local:StretchingTreeViewItem HorizontalAlignment="Stretch" Header="Stuff">
<Grid HorizontalAlignment="Stretch">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Label Grid.Column="0">Some random text</Label>
<TextBox Grid.Column="1" HorizontalAlignment="Stretch"></TextBox>
</Grid>
</local:StretchingTreeViewItem>
</local:StretchingTreeView>

Try something like this:
<TextBox Grid.Column="1" Width="{Binding Path=ActualWidth, RelativeSource={RelativeSource AncestorType={x:Type Grid}}, Mode=OneWay}"></TextBox>
Edit
Ok,i've found one solution Here. It basically creates a new class inheriting Treeview:
class StretchingTreeView : TreeView
{
protected override DependencyObject GetContainerForItemOverride()
{
return new StretchingTreeViewItem();
}
protected override bool IsItemItsOwnContainerOverride(object item)
{
return item is StretchingTreeViewItem;
}
}
class StretchingTreeViewItem : TreeViewItem
{
public StretchingTreeViewItem()
{
this.Loaded += new RoutedEventHandler(StretchingTreeViewItem_Loaded);
}
private void StretchingTreeViewItem_Loaded(object sender, RoutedEventArgs e)
{
// The purpose of this code is to stretch the Header Content all the way accross the TreeView.
if (this.VisualChildrenCount > 0)
{
Grid grid = this.GetVisualChild(0) as Grid;
if (grid != null && grid.ColumnDefinitions.Count == 3)
{
// Remove the middle column which is set to Auto and let it get replaced with the
// last column that is set to Star.
grid.ColumnDefinitions.RemoveAt(1);
}
}
}
protected override DependencyObject GetContainerForItemOverride()
{
return new StretchingTreeViewItem();
}
protected override bool IsItemItsOwnContainerOverride(object item)
{
return item is StretchingTreeViewItem;
}
}
Example usage:
<Window x:Class="WpfApplication2.Window2"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication2"
Title="Window2" Height="300" Width="300">
<Grid>
<local:StretchingTreeView HorizontalAlignment="Stretch" >
<local:StretchingTreeViewItem Header="Stuff" HorizontalAlignment="Stretch" HorizontalContentAlignment="Stretch" >
<Grid HorizontalAlignment="Stretch" >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Label Grid.Column="0">Some random text</Label>
<TextBox Grid.Column="1" ></TextBox>
</Grid>
</local:StretchingTreeViewItem>
</local:StretchingTreeView>
</Grid>

The core of the issue (and the way to fix it) is described here:
The default ControlTemplate for the TreeViewItem uses a grid of 3 columns x 2 rows, defined such that the content cannot stretch horizontally. The author also gives a modified style, that changes the grid so that the content can stretch.
Note that the modified style sets the HorizontalContentAlignment of TreeViewItem to Center, and that the ControlTemplate uses this property for aligning the content.
To achieve the desired effect, either set HorizontalContentAlignment to Stretch in the modified style, or override just that property on the TreeView (or specific TreeViewItems).
Missing the BasedOn="{StaticResource {x:Type TreeViewItem}}" part causes the TreeViewItem to revert to using the default ControlTemplate, with the non-stretchable grid.
<Style TargetType="TreeViewItem" BasedOn="{StaticResource {x:Type TreeViewItem}}">
<Setter Property="HorizontalContentAlignment" Value="Stretch"/>
</Style>
In a HierarchicalDataTemplate, the effect would be achieved by using the ItemContainerStyle property.
#pikoh's method of deriving from TreeView and TreeViewItem achieves the same, by modifying the grid from code.
Complete example:
<Window x:Class="WpfApp1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApp1"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Window.Resources>
<Style TargetType="TreeViewItem" BasedOn="{StaticResource {x:Type TreeViewItem}}">
<Setter Property="HorizontalContentAlignment" Value="Center" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="TreeViewItem">
<StackPanel>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"
MinWidth="19" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition />
</Grid.RowDefinitions>
<!-- Note that the following do not work, but I believe the top 2 should?! -->
<ToggleButton IsChecked="{Binding Path=IsExpanded, RelativeSource={RelativeSource TemplatedParent}}" ClickMode="Press" Name="Expander">
<ToggleButton.Style>
<Style TargetType="ToggleButton">
<Setter Property="UIElement.Focusable" Value="false" />
<Setter Property="FrameworkElement.Width" Value="16" />
<Setter Property="FrameworkElement.Height" Value="16" />
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="ToggleButton">
<Border Padding="5,5,5,5" Background="#00FFFFFF" Width="16" Height="16">
<Path Fill="#00FFFFFF" Stroke="#FF989898" Name="ExpandPath">
<Path.Data>
<PathGeometry Figures="M0,0L0,6L6,0z" />
</Path.Data>
<Path.RenderTransform>
<RotateTransform Angle="135" CenterX="3" CenterY="3" />
</Path.RenderTransform>
</Path>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="UIElement.IsMouseOver" Value="True">
<Setter TargetName="ExpandPath" Property="Shape.Stroke" Value="#FF1BBBFA" />
<Setter TargetName="ExpandPath" Property="Shape.Fill" Value="#00FFFFFF" />
</Trigger>
<Trigger Property="ToggleButton.IsChecked" Value="True">
<Setter TargetName="ExpandPath" Property="UIElement.RenderTransform">
<Setter.Value>
<RotateTransform Angle="180" CenterX="3" CenterY="3" />
</Setter.Value>
</Setter>
<Setter TargetName="ExpandPath" Property="Shape.Fill" Value="#FF595959" />
<Setter TargetName="ExpandPath" Property="Shape.Stroke" Value="#FF262626" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ToggleButton.Style>
</ToggleButton>
<Border x:Name="Bd"
HorizontalAlignment="Stretch"
BorderThickness="{TemplateBinding Border.BorderThickness}"
BorderBrush="{TemplateBinding Border.BorderBrush}"
Padding="{TemplateBinding Control.Padding}"
Background="{TemplateBinding Panel.Background}"
SnapsToDevicePixels="True"
Grid.Column="1">
<ContentPresenter x:Name="PART_Header"
Content="{TemplateBinding HeaderedContentControl.Header}"
ContentTemplate="{TemplateBinding HeaderedContentControl.HeaderTemplate}"
ContentStringFormat="{TemplateBinding HeaderedItemsControl.HeaderStringFormat}"
ContentTemplateSelector="{TemplateBinding HeaderedItemsControl.HeaderTemplateSelector}"
ContentSource="Header"
HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}"
SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" />
</Border>
<ItemsPresenter x:Name="ItemsHost" Grid.Column="1" Grid.Row="1" />
</Grid>
</StackPanel>
<ControlTemplate.Triggers>
<Trigger Property="TreeViewItem.IsExpanded" Value="False">
<Setter TargetName="ItemsHost" Property="UIElement.Visibility" Value="Collapsed" />
</Trigger>
<Trigger Property="ItemsControl.HasItems" Value="False">
<Setter TargetName="Expander" Property="UIElement.Visibility" Value="Hidden" />
</Trigger>
<Trigger Property="TreeViewItem.IsSelected" Value="True">
<Setter TargetName="Bd" Property="Panel.Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}" />
<Setter Property="TextElement.Foreground" Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}" />
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="TreeViewItem.IsSelected" Value="True" />
<Condition Property="Selector.IsSelectionActive" Value="False" />
</MultiTrigger.Conditions>
<Setter TargetName="Bd" Property="Panel.Background" Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" />
<Setter Property="TextElement.Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" />
</MultiTrigger>
<Trigger Property="UIElement.IsEnabled" Value="False">
<Setter Property="TextElement.Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Window.Resources>
<TreeView HorizontalAlignment="Stretch">
<TreeView.Resources>
<Style TargetType="TreeViewItem" BasedOn="{StaticResource {x:Type TreeViewItem}}">
<Setter Property="HorizontalContentAlignment" Value="Stretch"/>
</Style>
</TreeView.Resources>
<TreeViewItem Header="Stuff" HorizontalAlignment="Stretch">
<Grid HorizontalAlignment="Stretch">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Label Grid.Column="0">Some random text</Label>
<TextBox Grid.Column="1"></TextBox>
</Grid>
</TreeViewItem>
</TreeView>
</Window>

Due to an odd design decision by Microsoft when creating WPF, tree items can't stretch without replacing the control template.
See http://leecampbell.blogspot.com/2009/01/horizontal-stretch-on-treeviewitems.html
The required style is:
<Style TargetType="TreeViewItem"
BasedOn="{StaticResource {x:Type TreeViewItem}}">
<Setter Property="HorizontalContentAlignment"
Value="Center" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="TreeViewItem">
<StackPanel>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"
MinWidth="19" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition />
</Grid.RowDefinitions>
<!--
Note that the following do not work, but I believe the top 2 should?!
<ToggleButton IsChecked="{TemplateBinding IsExpanded}" ClickMode="Press" Name="Expander">
<ToggleButton IsChecked="{TemplateBinding Property=IsExpanded}" ClickMode="Press" Name="Expander">
<ToggleButton IsChecked="{TemplateBinding Path=IsExpanded}" ClickMode="Press" Name="Expander">
-->
<ToggleButton IsChecked="{Binding Path=IsExpanded, RelativeSource={RelativeSource TemplatedParent}}"
ClickMode="Press"
Name="Expander">
<ToggleButton.Style>
<Style TargetType="ToggleButton">
<Setter Property="UIElement.Focusable"
Value="false" />
<Setter Property="FrameworkElement.Width"
Value="16" />
<Setter Property="FrameworkElement.Height"
Value="16" />
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="ToggleButton">
<Border Padding="5,5,5,5"
Background="#00FFFFFF"
Width="16"
Height="16">
<Path Fill="#00FFFFFF"
Stroke="#FF989898"
Name="ExpandPath">
<Path.Data>
<PathGeometry Figures="M0,0L0,6L6,0z" />
</Path.Data>
<Path.RenderTransform>
<RotateTransform Angle="135"
CenterX="3"
CenterY="3" />
</Path.RenderTransform>
</Path>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="UIElement.IsMouseOver"
Value="True">
<Setter TargetName="ExpandPath"
Property="Shape.Stroke"
Value="#FF1BBBFA" />
<Setter TargetName="ExpandPath"
Property="Shape.Fill"
Value="#00FFFFFF" />
</Trigger>
<Trigger Property="ToggleButton.IsChecked"
Value="True">
<Setter TargetName="ExpandPath"
Property="UIElement.RenderTransform">
<Setter.Value>
<RotateTransform Angle="180"
CenterX="3"
CenterY="3" />
</Setter.Value>
</Setter>
<Setter TargetName="ExpandPath"
Property="Shape.Fill"
Value="#FF595959" />
<Setter TargetName="ExpandPath"
Property="Shape.Stroke"
Value="#FF262626" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ToggleButton.Style>
</ToggleButton>
<Border x:Name="Bd"
HorizontalAlignment="Stretch"
BorderThickness="{TemplateBinding Border.BorderThickness}"
BorderBrush="{TemplateBinding Border.BorderBrush}"
Padding="{TemplateBinding Control.Padding}"
Background="{TemplateBinding Panel.Background}"
SnapsToDevicePixels="True"
Grid.Column="1">
<ContentPresenter x:Name="PART_Header"
Content="{TemplateBinding HeaderedContentControl.Header}"
ContentTemplate="{TemplateBinding HeaderedContentControl.HeaderTemplate}"
ContentStringFormat="{TemplateBinding HeaderedItemsControl.HeaderStringFormat}"
ContentTemplateSelector="{TemplateBinding HeaderedItemsControl.HeaderTemplateSelector}"
ContentSource="Header"
HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}"
SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" />
</Border>
<ItemsPresenter x:Name="ItemsHost"
Grid.Column="1"
Grid.Row="1" />
</Grid>
</StackPanel>
<ControlTemplate.Triggers>
<Trigger Property="TreeViewItem.IsExpanded"
Value="False">
<Setter TargetName="ItemsHost"
Property="UIElement.Visibility"
Value="Collapsed" />
</Trigger>
<Trigger Property="ItemsControl.HasItems"
Value="False">
<Setter TargetName="Expander"
Property="UIElement.Visibility"
Value="Hidden" />
</Trigger>
<Trigger Property="TreeViewItem.IsSelected"
Value="True">
<Setter TargetName="Bd"
Property="Panel.Background"
Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}" />
<Setter Property="TextElement.Foreground"
Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}" />
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="TreeViewItem.IsSelected"
Value="True" />
<Condition Property="Selector.IsSelectionActive"
Value="False" />
</MultiTrigger.Conditions>
<Setter TargetName="Bd"
Property="Panel.Background"
Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" />
<Setter Property="TextElement.Foreground"
Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" />
</MultiTrigger>
<Trigger Property="UIElement.IsEnabled"
Value="False">
<Setter Property="TextElement.Foreground"
Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>

It seems like Grid's HorizontalAlignment Issue. I've tried it in .Net Framework 4 and it all works fine. Seems like in 4.5 even though you specify HorizontalAlignment as Stretch, it actually doesn't stretch it. So you can do a binding like below:
<Grid HorizontalAlignment="Stretch"
Width="{Binding RelativeSource={RelativeSource AncestorType={x:Type TreeViewItem}},Path=ActualWidth,Mode=OneTime}"
>
Cause you can see in the run time that TreeViewItem has Width expected but Grid doesn't.

All you need to do is add Grid.ColumnSpan='2' to the ControlTemplate of the TreeViewItem as shown below.
Thats it!
Explanation:
The default ControlTemplate places the Header Content in a Grid column that does not stretch. The Grid.ColumnSpan='2' instructs the Header content to span to the rest of the Grid.

Stretch Width of WPF RichTextBox within a TreeView

My objective is simply to have a RichTextBox consume the entire row width inside a TreeView. The XAML below will produce a TreeView with a RichTextBox element, but the width is only 1 character wide.
I have encountered the posts below concerning width Bugs in RichTextBox. These issues may have been fixed since a standalone RichTextBox has the expected width. Despite this I still tried creating Grids, setting Alignments to Stretch, and binding the FlowDocument PageWidth to parent without success.
[NEW]
I am adding a description of my application in case some would like to propose RTB alternatives. I have a TreeView that contains between 10-1000 RTB nodes. TextBox and TextBlock are not practical because I need full formatting and user editing.
WPF RichTextBox with no width set
A WPF RichTextBox + Button in a StackPanel => what a mess?
<TreeView>
<RichTextBox>
<FlowDocument>
<Paragraph>
<Run>
Hello
</Run>
</Paragraph>
</FlowDocument>
</RichTextBox>
</TreeView>
Thanks,

As you stated this is a known issue
The workaround provided is:
<TreeView Name="RTBContainer" >
<RichTextBox Width="{Binding Path=ActualWidth, ElementName=RTBContainer, Mode=OneWay}">
<FlowDocument >
<Paragraph>
<Run>
Hello
</Run>
</Paragraph>
</FlowDocument>
</RichTextBox>
</TreeView>

Your problem stems from the TreeViewItem default template. A TreeViewItem element wraps any content placed in a TreeView. The TreeViewItem's template is Grid containing three columns with the width of the first two set as Auto while width of the third is set as *. The element holding the Header content is in the second column and its content alignment set to Left.
I've extracted the template for the TreeViewItem and modified it so that the content container for the header spans the second and third columns and has its content alignment set to stretch.
(This is a modified clone of the WPF template so it's a bit lengthly)
<TreeView>
<TreeView.ItemContainerStyle>
<Style TargetType="TreeViewItem">
<!-- set the headers content to stretch -->
<Setter Property="Control.HorizontalContentAlignment" Value="Stretch"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="TreeViewItem" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" MinWidth="19" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition />
</Grid.RowDefinitions>
<ToggleButton IsChecked="False" ClickMode="Press" Name="Expander">
<ToggleButton.Style>
<Style TargetType="ToggleButton">
<Style.Resources>
<ResourceDictionary />
</Style.Resources>
<Setter Property="UIElement.Focusable">
<Setter.Value>
<s:Boolean>False</s:Boolean>
</Setter.Value>
</Setter>
<Setter Property="FrameworkElement.Width">
<Setter.Value>
<s:Double>16</s:Double>
</Setter.Value>
</Setter>
<Setter Property="FrameworkElement.Height">
<Setter.Value>
<s:Double>16</s:Double>
</Setter.Value>
</Setter>
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="ToggleButton">
<Border Padding="5,5,5,5" Background="#00FFFFFF" Width="16" Height="16">
<Path Fill="#00FFFFFF" Stroke="#FF989898" Name="ExpandPath">
<Path.Data>
<PathGeometry Figures="M0,0L0,6L6,0z" />
</Path.Data>
<Path.RenderTransform>
<RotateTransform Angle="135" CenterX="3" CenterY="3" />
</Path.RenderTransform>
</Path>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="UIElement.IsMouseOver">
<Setter Property="Shape.Stroke" TargetName="ExpandPath">
<Setter.Value>
<SolidColorBrush>#FF1BBBFA</SolidColorBrush>
</Setter.Value>
</Setter>
<Setter Property="Shape.Fill" TargetName="ExpandPath">
<Setter.Value>
<SolidColorBrush>#00FFFFFF</SolidColorBrush>
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>True</s:Boolean>
</Trigger.Value>
</Trigger>
<Trigger Property="ToggleButton.IsChecked">
<Setter Property="UIElement.RenderTransform" TargetName="ExpandPath">
<Setter.Value>
<RotateTransform Angle="180" CenterX="3" CenterY="3" />
</Setter.Value>
</Setter>
<Setter Property="Shape.Fill" TargetName="ExpandPath">
<Setter.Value>
<SolidColorBrush>#FF595959</SolidColorBrush>
</Setter.Value>
</Setter>
<Setter Property="Shape.Stroke" TargetName="ExpandPath">
<Setter.Value>
<SolidColorBrush>#FF262626</SolidColorBrush>
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>True</s:Boolean>
</Trigger.Value>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ToggleButton.Style>
</ToggleButton>
<!-- other problem was here set the Borders ColumnSpan to 2 -->
<Border BorderThickness="{TemplateBinding Border.BorderThickness}" Padding="{TemplateBinding Control.Padding}" BorderBrush="{TemplateBinding Border.BorderBrush}" Background="{TemplateBinding Panel.Background}" Name="Bd" SnapsToDevicePixels="True" Grid.Column="1" HorizontalAlignment="Stretch" Grid.ColumnSpan="2" >
<ContentPresenter Content="{TemplateBinding HeaderedContentControl.Header}" ContentTemplate="{TemplateBinding HeaderedContentControl.HeaderTemplate}" ContentStringFormat="{TemplateBinding HeaderedItemsControl.HeaderStringFormat}" ContentSource="Header" Name="PART_Header" HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}" SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" />
</Border>
<ItemsPresenter Name="ItemsHost" Grid.Column="1" Grid.Row="1" Grid.ColumnSpan="2" />
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="TreeViewItem.IsExpanded">
<Setter Property="UIElement.Visibility" TargetName="ItemsHost">
<Setter.Value>
<x:Static Member="Visibility.Collapsed" />
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>False</s:Boolean>
</Trigger.Value>
</Trigger>
<Trigger Property="ItemsControl.HasItems">
<Setter Property="UIElement.Visibility" TargetName="Expander">
<Setter.Value>
<x:Static Member="Visibility.Hidden" />
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>False</s:Boolean>
</Trigger.Value>
</Trigger>
<Trigger Property="TreeViewItem.IsSelected">
<Setter Property="Panel.Background" TargetName="Bd">
<Setter.Value>
<DynamicResource ResourceKey="{x:Static SystemColors.HighlightBrushKey}" />
</Setter.Value>
</Setter>
<Setter Property="TextElement.Foreground">
<Setter.Value>
<DynamicResource ResourceKey="{x:Static SystemColors.HighlightTextBrushKey}" />
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>True</s:Boolean>
</Trigger.Value>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="TreeViewItem.IsSelected">
<Condition.Value>
<s:Boolean>True</s:Boolean>
</Condition.Value>
</Condition>
<Condition Property="Selector.IsSelectionActive">
<Condition.Value>
<s:Boolean>False</s:Boolean>
</Condition.Value>
</Condition>
</MultiTrigger.Conditions>
<Setter Property="Panel.Background" TargetName="Bd">
<Setter.Value>
<DynamicResource ResourceKey="{x:Static SystemColors.ControlBrushKey}" />
</Setter.Value>
</Setter>
<Setter Property="TextElement.Foreground">
<Setter.Value>
<DynamicResource ResourceKey="{x:Static SystemColors.ControlTextBrushKey}" />
</Setter.Value>
</Setter>
</MultiTrigger>
<Trigger Property="UIElement.IsEnabled">
<Setter Property="TextElement.Foreground">
<Setter.Value>
<DynamicResource ResourceKey="{x:Static SystemColors.GrayTextBrushKey}" />
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>False</s:Boolean>
</Trigger.Value>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</TreeView.ItemContainerStyle>
<RichTextBox HorizontalAlignment="Stretch" HorizontalContentAlignment="Stretch">
<FlowDocument>
<Paragraph>
<Run>
Hello
</Run>
</Paragraph>
</FlowDocument>
</RichTextBox>
</TreeView>

How do I get a thicker drop shadow on my ToolTip?

I'm overriding my tooltips with the following:
<Style x:Key="{x:Type ToolTip}" TargetType="ToolTip">
<Setter Property="OverridesDefaultStyle" Value="True"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ToolTip">
<Grid>
<Grid.Background>
<SolidColorBrush />
</Grid.Background>
<mwt:SystemDropShadowChrome Color="#00FFFFFF" CornerRadius="5" Name="Shdw" SnapsToDevicePixels="True">
<Border CornerRadius="5">
<StackPanel>
<ContentPresenter TextBlock.Foreground="Black" />
</StackPanel>
</Border>
</mwt:SystemDropShadowChrome>
</Grid>
The Thickness value for the margin seems to have a maximum value of 5?
<ControlTemplate.Triggers>
<Trigger Property="ToolTipService.HasDropShadow">
<Setter Property="FrameworkElement.Margin" TargetName="Shdw">
<Setter.Value>
<Thickness>0,0,5,5</Thickness>
</Setter.Value>
</Setter>
<Trigger.Value>
<sys:Boolean>True</sys:Boolean>
</Trigger.Value>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
It would be nice to be able to see more of the dropshadow.
My bad for not posting all my code. Here it is with an edit based on the response from icebat:
<Style x:Key="{x:Type ToolTip}" TargetType="ToolTip">
<Setter Property="OverridesDefaultStyle" Value="True"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ToolTip">
<Grid>
<Grid.Background>
<SolidColorBrush />
</Grid.Background>
<mwt:SystemDropShadowChrome Color="#71000000" CornerRadius="5" Name="Shdw" SnapsToDevicePixels="True">
<Border CornerRadius="5">
<StackPanel>
<ContentPresenter TextOptions.TextRenderingMode="ClearType" TextOptions.TextFormattingMode="Display" TextBlock.FontFamily="Segoe UI" TextBlock.FontStretch="Normal" TextBlock.FontWeight="Normal" TextBlock.Foreground="Black" TextBlock.FontSize="13" Margin="18,8,16,4" HorizontalAlignment="Left" VerticalAlignment="Top" />
<Border HorizontalAlignment="Stretch" BorderThickness="0,1,0,0" BorderBrush="Gray" Margin="10,5,10,5" Grid.Column="0" Grid.Row="0" Grid.ColumnSpan="2">
<TextBlock Margin="8,4,0,0" FontWeight="Bold" Text="{x:Static res:AppStrings.Help_0_Footer}" FontSize="13" Foreground="#E3000000" />
</Border>
</StackPanel>
<Border.Background>
<LinearGradientBrush>
<LinearGradientBrush.StartPoint>
<Point X=".5" Y="0"/>
</LinearGradientBrush.StartPoint>
<LinearGradientBrush.EndPoint>
<Point X=".5" Y="1"/>
</LinearGradientBrush.EndPoint>
<LinearGradientBrush.GradientStops>
<GradientStop Color="#FFFFA200" Offset="1"/>
<GradientStop Color="White" Offset="0.305"/>
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>
</Border.Background>
</Border>
</mwt:SystemDropShadowChrome>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="ToolTipService.HasDropShadow" Value="True">
<Setter Property="Margin" TargetName="Shdw" Value="0,0,5,5"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
I still don't get a thicker dropshadow for a margin larger than 5.

Margin is not limited. To see more of the shadow you need to apply margin not to the SystemDropShadowChrome decorator itself but to its content:
<mwt:SystemDropShadowChrome Name="Shdw" CornerRadius="5">
<Border Name="shdwContent" CornerRadius="5">
<StackPanel>
<ContentPresenter TextBlock.Foreground="Black" />
</StackPanel>
</Border>
</mwt:SystemDropShadowChrome>
...
<ControlTemplate.Triggers>
<Trigger Property="ToolTipService.HasDropShadow" Value="True">
<Setter Property="Margin" TargetName="ShdwContent" Value="0,0,5,5">
</Trigger>
</ControlTemplate.Triggers>
And as a side note, right now you are using transparent color as shadow color (#00FFFFFF). If that`s not changed with some triggers or by other means, you won`t see any shadow.

WPF - Implement ItemTemplate for an ItemsPresenter?

I've been working on a SplitButton control for WPF and its basically done, but I'm trying to go through all the possible properties that can be set on it and make sure they are actually implemented. I mostly have only two properties left to implement which is the ItemTemplate and ItemTemplateSelector (and AlternationCount, okay so 3 properties).
I was able to get the HeaderTemplate and HeaderTemplateSelector working by binding the ContentTemplate and ContentTemplateSelector to them on a ContentPresenter. This is for the button part of the control though. For the drop-drop part of the control I'm using a Popup, Border, and ItemsPresenter. The problem is that I can't figure how to set the ItemTemplate and ItemTemplateSelector properties for the ItemsPresenter.
Any ideas?
Update:
The full source code for the SplitButton is now available at:
http://anothersplitbutton.codeplex.com/
Here's the Luna.NormalColor.xaml file:
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:WpfSplitButton="clr-namespace:WpfSplitButton"
xmlns:mwt="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Luna"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<!-- SplitButtonHeader Style -->
<Style x:Key="{x:Type WpfSplitButton:SplitButtonHeader}"
TargetType="{x:Type WpfSplitButton:SplitButtonHeader}">
<Style.Resources>
<Style x:Key="ButtonFocusVisual">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate>
<Rectangle Margin="2"
StrokeThickness="1"
Stroke="Black"
StrokeDashArray="1 2"
SnapsToDevicePixels="True" />
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Style.Resources>
<Style.Setters>
<Setter Property="FocusVisualStyle"
Value="{StaticResource ButtonFocusVisual}" />
<Setter Property="HorizontalContentAlignment"
Value="Center" />
<Setter Property="PastLeftDetection"
Value="True" />
<Setter Property="VerticalContentAlignment"
Value="Center" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<mwt:ButtonChrome x:Name="Chrome"
BorderBrush="{TemplateBinding Border.BorderBrush}"
RenderDefaulted="{TemplateBinding Button.IsDefaulted}"
RenderMouseOver="{TemplateBinding UIElement.IsMouseOver}"
RenderPressed="{TemplateBinding ButtonBase.IsPressed}"
SnapsToDevicePixels="True">
<Grid Background="{TemplateBinding ButtonBase.Background}">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<ContentPresenter Content="{TemplateBinding ContentControl.Content}"
ContentTemplate="{TemplateBinding ButtonBase.ContentTemplate}"
ContentTemplateSelector="{TemplateBinding ButtonBase.ContentTemplateSelector}"
HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}"
Margin="{TemplateBinding Control.Padding}"
RecognizesAccessKey="True"
SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}"
VerticalAlignment="{TemplateBinding Control.VerticalContentAlignment}" />
<Border x:Name="PART_DropDownInitiator"
Background="Transparent"
BorderBrush="{Binding Path=BorderBrush, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type WpfSplitButton:SplitButtonHeader}}}"
BorderThickness="1,0,0,0"
Grid.Column="1"
HorizontalAlignment="Stretch"
Margin="0,0,0,0"
Padding="4,0,4,0"
VerticalAlignment="Stretch">
<Path Fill="{Binding Path=Foreground, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type WpfSplitButton:SplitButtonHeader}}}"
VerticalAlignment="Center">
<Path.Style>
<Style>
<Setter Property="Path.Fill"
Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}" />
<Style.Triggers>
<Trigger Property="WpfSplitButton:SplitButton.IsMouseOver"
Value="True">
<Setter Property="Path.Fill"
Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}" />
</Trigger>
</Style.Triggers>
</Style>
</Path.Style>
<Path.Data>
<PathGeometry>
<PathGeometry.Figures>
<PathFigureCollection>
<PathFigure IsClosed="True"
StartPoint="0,0">
<PathFigure.Segments>
<PathSegmentCollection>
<LineSegment Point="8,0" />
<LineSegment Point="4,5" />
</PathSegmentCollection>
</PathFigure.Segments>
</PathFigure>
</PathFigureCollection>
</PathGeometry.Figures>
</PathGeometry>
</Path.Data>
</Path>
</Border>
</Grid>
</mwt:ButtonChrome>
<ControlTemplate.Triggers>
<Trigger Property="UIElement.IsKeyboardFocused"
Value="True">
<Setter TargetName="Chrome"
Property="mwt:ButtonChrome.RenderDefaulted"
Value="True" />
</Trigger>
<Trigger Property="ToggleButton.IsChecked"
Value="True">
<Setter TargetName="Chrome"
Property="mwt:ButtonChrome.RenderPressed"
Value="True" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style.Setters>
</Style>
<!-- SplitButton -->
<Style x:Key="{x:Type WpfSplitButton:SplitButton}"
TargetType="{x:Type WpfSplitButton:SplitButton}">
<Style.Resources>
<LinearGradientBrush x:Key="ButtonNormalBackgroundFill"
EndPoint="0.5,1"
StartPoint="0.5,0">
<LinearGradientBrush.GradientStops>
<GradientStop Color="#FFFFFFFF"
Offset="0" />
<GradientStop Color="#FFF0F0EA"
Offset="0.9" />
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>
<SolidColorBrush x:Key="ButtonBorder"
Color="#FF003C74" />
</Style.Resources>
<Setter Property="AutoUpdateHeader"
Value="True" />
<Setter Property="Background"
Value="{StaticResource ButtonNormalBackgroundFill}" />
<Setter Property="BorderBrush"
Value="{StaticResource ButtonBorder}" />
<Setter Property="BorderThickness"
Value="1" />
<Setter Property="Foreground"
Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" />
<Setter Property="HorizontalContentAlignment"
Value="Center" />
<Setter Property="Padding"
Value="4,4,4,4" />
<Setter Property="VerticalContentAlignment"
Value="Center" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type WpfSplitButton:SplitButton}">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<WpfSplitButton:SplitButtonHeader x:Name="PART_Header"
Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
Content="{TemplateBinding Header}"
ContentTemplate="{TemplateBinding HeaderTemplate}"
ContentTemplateSelector="{TemplateBinding HeaderTemplateSelector}"
Cursor="{TemplateBinding Cursor}"
Foreground="{TemplateBinding Foreground}"
Grid.Row="0"
HorizontalAlignment="Stretch"
HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
Padding="{TemplateBinding Padding}"
VerticalAlignment="Stretch"
VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" />
<Popup x:Name="PART_Popup"
AllowsTransparency="True"
Grid.Row="1"
IsOpen="{Binding Path=IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
MinWidth="{Binding Path=ActualWidth, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type WpfSplitButton:SplitButton}}}"
Placement="Bottom"
PlacementTarget="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type WpfSplitButton:SplitButton}}}"
PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}"
StaysOpen="False">
<mwt:SystemDropShadowChrome Color="Transparent">
<Border x:Name="DropDownBorder"
Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}">
<ItemsPresenter SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
</Border>
</mwt:SystemDropShadowChrome>
</Popup>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="IsEnabled"
Value="False">
<Setter Property="Foreground"
Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" />
</Trigger>
</Style.Triggers>
</Style>
</ResourceDictionary>
Update 2
I tried switching out the ItemsPresenter with a ItemsControl, but I can't seem to get the ItemTemplate property to do anything. Here's the changed section of code:
<ItemsControl DataContext="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type WpfSplitButton:SplitButton}}}"
AlternationCount="{TemplateBinding AlternationCount}"
IsTabStop="{TemplateBinding IsTabStop}"
IsTextSearchEnabled="{TemplateBinding IsTextSearchEnabled}"
ItemContainerStyle="{TemplateBinding ItemContainerStyle}"
ItemContainerStyleSelector="{TemplateBinding ItemContainerStyleSelector}"
ItemBindingGroup="{TemplateBinding ItemBindingGroup}"
ItemsPanel="{TemplateBinding ItemsPanel}"
ItemsSource="{Binding Path=Items}"
ItemStringFormat="{TemplateBinding ItemStringFormat}"
ItemTemplateSelector="{TemplateBinding ItemTemplateSelector}"
SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="HELLO" />
</DataTemplate>
</ItemsControl.ItemTemplate>

Have you considered using an ItemsControl instead of the ItemsPresenter? This would give you the ItemTemplate and ItemTemplateSelector property as well as the AlternationCount property.
Update:
I got it to work just fine using the ItemsControl like you posted above using the following line to bind to the ItemsTemplate Property in your Classic.xaml file:
ItemTemplate="{TemplateBinding ItemsTemplate, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type WpfSplitButton:SplitButton}}}"
Then in your MainWindow's Resources i just added the following template:
<DataTemplate x:Key="Test">
<MenuItem Header="{Binding}" />
</DataTemplate>
Then i set the ItemTemplate Property on the SplitButton:
ItemTemplate="{StaticResource Test}"
So just hook up your ItemSource and you are good to go... i just used a simple string[] in the code behind...
Hope this helps!