For a message you would use "Show custom dialog box".
You can also create a "New Window"
But when I used:
Goto layout "Approval"
New Window [Name:Approval; Height:100;Width:100; top:100;Left:100; Style:Dialog]
It appeared 2 windows for Approval. How was it?
The sample is mislead in the link. Try New Window, then goto the new layout.