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

<UserControl x:Class="RainmeterStudio.UI.Panels.ToolboxPanel"
             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" 
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <UserControl.Resources>
        
        <Style x:Key="ToolboxListViewStyle" TargetType="ListView">
            <Style.Triggers>
                <Trigger Property="HasItems" Value="False">
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate TargetType="ListView">
                                <Grid>
                                    <TextBlock TextAlignment="Center"
                                               HorizontalAlignment="Center"
                                               VerticalAlignment="Center"
                                               TextWrapping="Wrap" 
                                               Text="There are no toolbox items available for the active document." />
                                </Grid>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </Trigger>
            </Style.Triggers>
        </Style>
        
    </UserControl.Resources>
    
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition />
        </Grid.RowDefinitions>
        
        <DockPanel Grid.Row="0" LastChildFill="True">
            <Button DockPanel.Dock="Right">Search</Button>
            <TextBox Name="searchTextBox"/>
        </DockPanel>
        
        <ListView Name="listItems"
                  Style="{StaticResource ToolboxListViewStyle}"
                  Grid.Row="2">
            <ListView.ItemContainerStyle>
                <Style TargetType="ListViewItem">
                    <EventSetter Event="PreviewMouseMove" Handler="Item_PreviewMouseMove" />
                    <EventSetter Event="PreviewMouseDoubleClick" Handler="Item_PreviewMouseDoubleClick" />
                </Style>
            </ListView.ItemContainerStyle>
            <ListView.ItemTemplate>
                <DataTemplate>
                    <DockPanel LastChildFill="True" ToolTip="{Binding ToolTip}">
                        <Image Width="16" Height="16" Source="{Binding Icon}" DockPanel.Dock="Left" />
                        <TextBlock Text="{Binding DisplayText}" />
                    </DockPanel>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
        
    </Grid>
</UserControl>