Show message box (form) while script is running

Hello,

I´m working on a installtion script which should install a .msi package and while the installation is running the user should see a message box (form) "installation running".

My problem is to get the message box (form). If I use "$Form.ShowDialog()" the script will stop as long as the form is open. And if I use "$form.Show()" I cann´t see the label text because the label is transparent.

Here is my script:

    Add-Type -AssemblyName System.Windows.Forms

    $Form = New-Object system.Windows.Forms.Form
    $Form.Text = "Installation"
    $Form.AutoSize = $True
    $Form.AutoSizeMode = "GrowAndShrink"
    $Font = New-Object System.Drawing.Font("Times New Roman",18 [System.Drawing.FontStyle]::Italic)
   
    $Form.Font = $Font
    $form.FormBorderStyle = [System.Windows.Forms.FormBorderStyle]::FixedSingle

    $handler_form_Load = { $form.Location = New-Object System.Drawing.Point(600, 200) }
    $form.add_Load($handler_form_Load)
 
    $Label = New-Object System.Windows.Forms.Label
    $Label.Text = "Installation running...."
    $Label.AutoSize = $True

    $Form.Controls.Add($Label)

    # $Form.ShowDialog() | out-null
    $form.Show() | out-null

    #give the form focus
    $form.Focus() | out-null

    # Here the installation should start

    $form.Close()

Regards, Martin Fischer