How to apply DesktopAcrylicBackdrop to a uno built window

[cconner100]

Using the window created by Builder.Window i am trying in Windows only to apply a DesktopAcrylicBackdrop;

I am using the Window returned by Builder.Window then settings the window.SystemBackdrop = new DesktopAcrylicBackdrop(); which seems to have no effect at all.

In addition when i check to see what type the window is, it is not a WindowEx which is needed for the SystemBackdrop to work?

Any ideas