CorelCad PDF Underlays in Sheet View

I'm using the PDF Underlay feature in CorelCAD 2020 for Windows.  After inserting a PDF underlay in Model space, I want to add text in sheet space, but the text disappears beneath the underlay.  I've tried changing the display order of both the underlay (to back) and the text (to front), but the text is still behind the underlay.  How do I get text (or any graphics) to show on top of an underlay?  By the way, I'm able to draw on top of the underlay in Model space and it continues to show in Sheet space.  It's only when I draw in Sheet space in a view port that the graphic entities are behind the underlay.  What can be done?