rainmeter-studio/RainmeterStudio/UI/Panels/ProjectPanel.xaml

<UserControl x:Class="RainmeterStudio.UI.Panels.ProjectPanel"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:ctrl="clr-namespace:RainmeterStudio.UI.Controller"
             xmlns:ui="clr-namespace:RainmeterStudio.UI"
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <UserControl.Resources>
        <ctrl:IconProviderConverter x:Key="IconConverter" />
    </UserControl.Resources>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
            <RowDefinition />
        </Grid.RowDefinitions>
        
        <!-- Toolbar -->
        <ToolBar Grid.Row="0" ToolBarTray.IsLocked="True">
            <Button DataContext="{Binding SyncWithActiveViewCommand}"
                    Style="{StaticResource CommandButtonStyle}">
                <Image Width="16" Height="16" Source="{Binding Icon}" />
            </Button>
            <Button DataContext="{Binding RefreshCommand}"
                    Style="{StaticResource CommandButtonStyle}">
                <Image Width="16" Height="16" Source="{Binding Icon}" />
            </Button>
            <Button DataContext="{Binding CollapseAllCommand}"
                    Style="{StaticResource CommandAutoHideButtonStyle}">
                <Image Width="16" Height="16" Source="{Binding Icon}" />
            </Button>
            <Button DataContext="{Binding ExpandAllCommand}"
                    Style="{StaticResource CommandAutoHideButtonStyle}">
                <Image Width="16" Height="16" Source="{Binding Icon}" />
            </Button>
            <ToggleButton Name="toggleShowAllFiles"
                    DataContext="{Binding ShowAllFilesCommand}"
                    Style="{StaticResource CommandButtonStyle}">
                <Image Width="16" Height="16" Source="{Binding Icon}" />
            </ToggleButton>
        </ToolBar>
        
        <!-- Project item tree  -->
        <TreeView Grid.Row="2" Name="treeProjectItems">
            <TreeView.ItemContainerStyle>
                <Style TargetType="{x:Type TreeViewItem}">
                    <Setter Property="IsExpanded" Value="{Binding Data.IsExpanded, Mode=TwoWay}" />
                    <Setter Property="IsSelected" Value="{Binding Data.IsSelected, Mode=TwoWay}" />
                    <EventSetter Event="Expanded" Handler="TreeViewItem_ExpandedOrCollapsed" />
                    <EventSetter Event="Collapsed" Handler="TreeViewItem_ExpandedOrCollapsed" />
                </Style>
            </TreeView.ItemContainerStyle>
            <TreeView.ItemTemplate>
                <HierarchicalDataTemplate ItemsSource="{Binding Children}">
                    <DockPanel LastChildFill="True">
                        <Image DockPanel.Dock="Left" Width="16" Height="16" Source="{Binding Data.Reference.Data, Converter={StaticResource IconConverter}}" />
                        <TextBlock Text="{Binding Data.Name}" />
                    </DockPanel>
                </HierarchicalDataTemplate>
            </TreeView.ItemTemplate>
        </TreeView>
    </Grid>
</UserControl>