Flicker on DragMove of Border-less WPF Custom Window

Question

I have a custom, border-less window intended to act as a base form for future WPF projects. I've managed to simulate near all of the native window behaviours, but I'm having a problem with DragMove. I wanted the window to reposition itself above the task bar when the user drags the its title bar behind the windows task bar, so that the whole window is visible. I managed to do this by overriding the OnLocationChanged method, because all the mouse related handlers are blocked during DragMove.

This works like a charm, except I get a flicker when dragging the title bar along the windows task bar. I can see it is trying to redraw the window where it would have been, down below, and then it immediately redraws the window again in the intended place.

How can I interrupt this redrawing properly? Many Thanks!

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This, this, this and this SO question did not help me at all, unfortunately. Here is an extract of my code:

protected override void OnLocationChanged(EventArgs e)
{
    base.OnLocationChanged(e);

    var activeScreenHeight = System.Windows.Forms.Screen.FromHandle(new WindowInteropHelper(this).Handle).WorkingArea.Bottom - ToolbarSnapThreshold;
    if (activeScreenHeight < this.RestoreBounds.Top)
    {
        this.Top = activeScreenHeight - this.RestoreBounds.Height + ToolbarSnapThreshold;
    }
}

protected void MaximizeOrRestore()
{
    this.WindowState = (this.WindowState == WindowState.Normal) ? WindowState.Maximized : WindowState.Normal;
    this.lastNonMinimizedState = this.WindowState;
}

protected void RestoreAndDragMove(MouseButtonState leftMouseButtonState)
{
    if (leftMouseButtonState == MouseButtonState.Pressed)
    {
        if (this.WindowState == WindowState.Maximized)
        {
            var activeScreenWidth = System.Windows.Forms.Screen.FromHandle(new WindowInteropHelper(this).Handle).Bounds.Width;
            var windowCurrentWidth = this.RestoreBounds.Width;

            var windowPositionAdjustX = this.relativeMousePositionX - (windowCurrentWidth / 2);

            if (windowPositionAdjustX < 0)
            {
                windowPositionAdjustX = 0;
            }
            else if (windowPositionAdjustX + windowCurrentWidth > activeScreenWidth)
            {
                windowPositionAdjustX = activeScreenWidth - windowCurrentWidth;
            }

            this.WindowState = WindowState.Normal;
            this.lastNonMinimizedState = this.WindowState;
            this.Left = windowPositionAdjustX - this.relativeMousePositionX + this.originalMousePositionX;
            this.Top = 0 - this.relativeMousePositionY + this.originalMousePositionY;
        }

        this.DragMove();
    }
}

private void Window_TitleBarClicked(object sender, MouseButtonEventArgs e)
{
    if (e.LeftButton == MouseButtonState.Pressed)
    {
        this.relativeMousePositionX = e.GetPosition(this).X;
        this.relativeMousePositionY = e.GetPosition(this).Y;
        this.originalMousePositionX = System.Windows.Forms.Cursor.Position.X;
        this.originalMousePositionY = System.Windows.Forms.Cursor.Position.Y;

        if (e.ClickCount == 2)
        {
            this.MaximizeOrRestore();
        }
    }
}