Has anyone ever had any luck automating Visio drawing modifications?

I'm trying to simply edit some text on a drawing. The below code seems to "work" as it does change the text and save it as a new file. But for some reason, Visio always pops open for a second. Don't know how to run it hidden, like I can Excel.

It also always displays the original file name in the console for a second. Maybe something weird with the .Open(), but I can't find any reason why it would do that.

Any ideas?

 Code:
Break On

$DrawingFile = @ScriptDir+"\Drawing1.vsdx"
$date = Join(Split(@Date,"/"),"")
$ext = SubStr($DrawingFile, InStrRev($DrawingFile,"."))
$newDrawingFile = Split($DrawingFile, $ext)[0] + "_" + $date + $ext

$oVisio = CreateObject("VISIO.Application")
$oVisio.Visible = 0
$oVisio.DisplayAlerts = 0

$oVisio.Documents.Open($DrawingFile)

$textBox1 = $oVisio.ActiveWindow.Page.Shapes.ItemFromID(1).Characters
$textBox1.Text = "987654321"

$nul = $oVisio.ActiveDocument.SaveAs($newDrawingFile)

$oVisio.Quit
$oVisio = 0