Scrollbar not working in wrappanel

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WPF

Scrollbar

hi,

i have window with a collection of user control , these user control can drag in the window. my scenario is
add 2 user control
maximize window
one of the user control drag into bottom right position
minimize the window
then the only one user control is showing and there is no scroll bar



window XAML

<Grid  Grid.Row="0" >
            <ScrollViewer HorizontalScrollBarVisibility="Visible">
                <ItemsControl ItemsSource="{Binding  UsercontrolCollectionDetails,
                       UpdateSourceTrigger=PropertyChanged,Mode=TwoWay}">
                    <ItemsControl.ItemsPanel>
                        <ItemsPanelTemplate>
                            <WrapPanel  
                                 ScrollViewer.HorizontalScrollBarVisibility="Visible" 
                                 ScrollViewer.VerticalScrollBarVisibility="Visible" 
                                        HorizontalAlignment="Left"
                                        VerticalAlignment="Top"/>
                        </ItemsPanelTemplate>
                    </ItemsControl.ItemsPanel>
                </ItemsControl>
        </Grid>

user control .cs file

private void root_MouseMove(object sender, MouseEventArgs e)
        {
            var element = sender as UcNetworkLayoutGraphicalView;
            if (isInDrag && element != null && e.LeftButton == MouseButtonState.Pressed)
            {
                currentPoint = e.GetPosition(null);
                var window = Window.GetWindow(this);
                if (currentPoint.X > 10 && currentPoint.X < window.ActualWidth - 25
                    && currentPoint.Y > 10 && currentPoint.Y < window.ActualHeight - 85)
                {
                    transform.X += currentPoint.X - anchorPoint.X;
                    transform.Y += (currentPoint.Y - anchorPoint.Y);
                    this.RenderTransform = transform;
                    anchorPoint = currentPoint;
                }
               
            }
        }

What I have tried:

i googled but didn't get any solution .