Refreshing browser from other runspace

browser.ps1

$syncHash = [hashtable]::Synchronized(@{ 
            Browser = $null
            Window = $null
         })

$psCmd = [powershell]::Create()
$newRunspace = [RunspaceFactory]::CreateRunspace()
$newRunspace.Open()

$newRunspace.SessionStateProxy.SetVariable('syncHash',  $syncHash)
$psCmd.Runspace = $newRunspace

$sb = {
    $c= 0
    while ($true) {
        Start-Sleep -Seconds 10
        $c++

        if ($c % 2) {
            $syncHash.Window.Dispatcher.invoke([action] {
            try {
                $syncHash.Window.Title = "google"
                $syncHash.Browser.Navigate('http://www.google.com') 
                $syncHash.Window.InvalidateVisual()
                } catch {}
            })
        }
        else {
            $syncHash.Window.Dispatcher.invoke([action] {
            try {
                $syncHash.Window.Title = "bing"
                $syncHash.Browser.Navigate('http://www.bing.com') 
                $syncHash.Window.InvalidateVisual()
            } catch {}
            })
        }
    }
}

$psCmd.AddScript($sb)
$psCmd.BeginInvoke()

[void][System.Reflection.Assembly]::LoadWithPartialName('presentationframework')
[xml]$xaml = @'
<Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="PowerShell HTML GUI" WindowStartupLocation="Manual">
    <Grid>
        <WebBrowser
            HorizontalAlignment="Left"
            Width="415"
            Height="340"
            Margin="10,10,0,0"
            VerticalAlignment="Top"
            Name="WebBrowser"
        />
    </Grid>
</Window>
'@
$reader = New-Object System.Xml.XmlNodeReader($xaml)
$Form = [Windows.Markup.XamlReader]::Load($reader)
$Form.Width = 415
$Form.Height = 340
$Form.Topmost = $True
$WebBrowser = $Form.FindName('WebBrowser')
$WebBrowser.add_Loaded({$this.Navigate('http://www.bing.com')})
$syncHash.Window = $Form
$syncHash.Browser = $WebBrowser
$Form.ShowDialog()
$psCmd.Stop()