Photo-Paint for Mac, Effect tool, Smudge doesn't smudge across layers ie. Merge Source doesn't work (like it did in PP for windows)

I'm switching from Corel Draw Suite for Windows to Corel Draw Suite for Mac (Studio).  I'v followed all the Help threads I could find, including on-line help, but I am unable to make the Merge Source function (PhotoPaint/Effect Tool/Smudge/Brush Settings/Dab Attributes/Merge Source) work as it did in Windows ie. smudge between/across layers.