a new build with opacity is here:

http://www.kixforms.org/assets/files/kixforms/developer/kixforms.msi

 Code:
Break On

$System = CreateObject("Kixforms.System")

$Form = $System.Form()
$Form.ClientWidth = 640
$Form.ClientHeight = 480

$Form.Opacity = 0.5

$Button = $Form.Controls.Add($System.Button())
$Button.Text = "Exit"
$Button.Center

$Form.Center
$Form.Show
While $Form.Visible
 $= Execute($Form.DoEvents())
Loop

Exit 0