Powershell: Nur max. einen Runspace per Button starten?

$Script:MountImageGroupBox.Controls.Add(( Add-Button -Button "MountImageButton" -Scope "Script" -Location "280,15" -Size "120,25" -Text "Mount" ))  

$Script:MountImageButton.Add_Click({
$Script:MountImageButton.Enabled = $false
IF ((Test-Path Variable:DeleteButton) -eq $true) {$Window.Controls.Remove($Script:DeleteButton)}

Start-Progress -Job ([scriptblock]::create("Mount-WindowsImage –ImagePath ""$Project\Betriebssystem\sources\install.wim"" –Index $($Settings["Index"]) -Path ""$Project\Mount"" –Optimize"))  

$Settings["install.wim"] = $Script:MountImageRadioButton.Checked  
$Settings["boot.wim"] = $Script:MountBootImageRadioButton.Checked  
Write-Settings $Settings $Settings_xmlFile

$Window.Controls.Clear()

Set-WindowDesign
Set-Parameter_Image

Mounted-Info_GroupBox
Mounted-Add_GroupBox
Mounted-Image_GroupBox

})

$Script:MountedImageGroupBox.Controls.Add(( Add-Button -Button "DismountImageButton" -Scope "Script" -Location "280,15" -Size "120,25" -Text "Dismount" ))  

$Script:DismountImageButton.Add_Click({
Start-Progress -Job ([scriptblock]::create("Dismount-WindowsImage –Path ""$Project\Mount"" -Save -CheckIntegrity -ScratchDirectory ""$Project\Temp"""))  

$Window.Controls.Clear() 

Set-WindowDesign
Set-Parameter_Image

Mount-Info_GroupBox
Mount-Add_GroupBox
Mount-Image_GroupBox

Delete-Project
})

 
Function Start-Progress {
  
  param
  (
    [Parameter(Mandatory = $true)]
    [scriptblock]$Job,
    [Parameter(Mandatory = $false)]
    [String]$Text = ([String]$Job).Split(" ")  
  )
  
  $newPowerShell = [powershell]::Create().AddScript($Job) 
  $Run = $newPowerShell.BeginInvoke() 
  
  $ProgressBar = New-Object System.Windows.Forms.ProgressBar
  $ProgressBar.Name = "ProgressBar"  
  $ProgressBar.Style = "Continuous"  
  $Progressbar.ForeColor = "lightblue"  
  $Progressbar.BackColor= "white"  
  $ProgressBar.Location = "340,505"  
  $ProgressBar.Size = "620,20"  
  $Window.Controls.Add($ProgressBar)
  
  $Script:ProgressBar_Text = New-Object System.Windows.Forms.Label
  $Script:ProgressBar_Text.Location = New-Object System.Drawing.Size(340,290)
  $Script:ProgressBar_Text.Size = New-Object System.Drawing.Size(620,20)
  $Script:ProgressBar_Text.ForeColor = "red"  
  $Script:ProgressBar_Text.Text = $Text
  $Window.Controls.Add($Script:ProgressBar_Text) 

  $i = 0
  while ($Run.IsCompleted -eq $false) {
  
  $ProgressBar.Value = $i
  Start-Sleep -Milliseconds 500
  
  $i++
  IF ($i -eq 101) {$i = 0}

  IF ($Run.IsCompleted -eq $true) {break}
  }

  $Window.Controls.Remove($ProgressBar)
  $Window.Controls.Remove($Script:ProgressBar_Text)

  $newPowerShell.EndInvoke($Run)
  $newPowerShell.Runspace.Close()
  $newPowerShell.Dispose()
}