ItemsControl which has the content control

People.cs

public class People : List<Person> { }

public class Person
{
    public string First { get; set; }
    public string Last { get; set; }
    public string Phone { get; set; }
}

ResizeThumb.cs

public class ResizeThumb : Thumb
{
    public ResizeThumb() => DragDelta += new DragDeltaEventHandler(this.ResizeThumb_DragDelta);

    private void ResizeThumb_DragDelta(object sender, DragDeltaEventArgs e)
    {
        if (this.DataContext is Control designerItem)
        {
            double deltaVertical, deltaHorizontal;

            switch (VerticalAlignment)
            {
                case VerticalAlignment.Bottom:
                    deltaVertical = Math.Min(-e.VerticalChange, designerItem.ActualHeight - designerItem.MinHeight);
                    designerItem.Height -= deltaVertical;
                    break;
                case System.Windows.VerticalAlignment.Top:
                    deltaVertical = Math.Min(e.VerticalChange, designerItem.ActualHeight - designerItem.MinHeight);
                    Canvas.SetTop(designerItem, Canvas.GetTop(designerItem) + deltaVertical);
                    designerItem.Height -= deltaVertical;
                    break;
                default:
                    break;
            }

            switch (HorizontalAlignment)
            {
                case System.Windows.HorizontalAlignment.Left:
                    deltaHorizontal = Math.Min(e.HorizontalChange, designerItem.ActualWidth - designerItem.MinWidth);
                    Canvas.SetLeft(designerItem, Canvas.GetLeft(designerItem) + deltaHorizontal);
                    designerItem.Width -= deltaHorizontal;
                    break;
                case System.Windows.HorizontalAlignment.Right:
                    deltaHorizontal = Math.Min(-e.HorizontalChange, designerItem.ActualWidth - designerItem.MinWidth);
                    designerItem.Width -= deltaHorizontal;
                    break;
                default:
                    break;
            }
        }
        e.Handled = true;
    }
}

window.xaml

<Window.Resources>
    <local:People x:Key="People">
        <local:Person First="Joe" Last="Smith" Phone="303-555-5555"/>
        <local:Person First="Jenny" Last="Johnson" Phone="720-867-5309" />
        <local:Person First="Frank" Last="Wright" Phone="202-555-5555" />
    </local:People>

    <Style TargetType="{x:Type ContentControl}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ContentControl}">
                    <Grid DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}">
                        <Control x:Name="resizer">
                            <Control.Style>
                                <Style TargetType="{x:Type Control}">
                                    <Setter Property="Template">
                                        <Setter.Value>
                                            <ControlTemplate TargetType="{x:Type Control}">
                                                <Grid Margin="-3">
                                                    <local:ResizeThumb Width="7" Height="7" Margin="-2" Cursor="SizeNWSE" VerticalAlignment="Bottom" HorizontalAlignment="Right"/>
                                                </Grid>
                                            </ControlTemplate>
                                        </Setter.Value>
                                    </Setter>
                                </Style>
                            </Control.Style>
                        </Control>
                        <ContentPresenter Content="{TemplateBinding Content}"/>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

</Window.Resources>


<ItemsControl Margin="10"
            ItemsSource="{Binding Source={StaticResource People}}">

    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <UniformGrid Rows="1" />
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>

    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <Canvas>
                <ContentControl  Width="100" Height="100" >
                    <Grid>
                        <Ellipse Fill="Silver">
                            <Ellipse.Effect>
                                <DropShadowEffect Color="Black" Direction="320"  ShadowDepth="6"  Opacity="0.5"/>
                            </Ellipse.Effect>
                        </Ellipse>
                        <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
                            <TextBlock Margin="3,3,3,0" Text="{Binding Path=First}"/>
                            <TextBlock Margin="3,0,3,7" Text="{Binding Path=Last}"/>
                        </StackPanel>
                    </Grid>
                </ContentControl>
            </Canvas>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
    <ItemsControl.ItemContainerStyle>
        <Style TargetType="{x:Type ContentPresenter}">
            <Style.Triggers>
                <Trigger Property="IsMouseOver" Value="True">
                    <Setter Property="Grid.ZIndex" Value="1"/>
                </Trigger>
            </Style.Triggers>
        </Style>
    </ItemsControl.ItemContainerStyle>
</ItemsControl>

To reproduce create a .Net Core WPF app. Place the window.xaml code into the main page. Then create separate files for people.cs and ResizeThumb.cs and provide the proper namespacing in the main windows xaml.