Well, yes, from what I observed, Fences will take over Desktop icons when active. So if you need your Desktop icons Not to be on your left monitor. Create a Fence and put all you desktop icons, all of it, into that fence, move it to your right monitor. And set Fences rule all new icons on desktop move to that Fence. From there it should work.
Note : Using Portal Fences on Desktop folder will not work for your requirement.
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