Grass node not working on landscape in 5.4?

Ok, I know the node does work. I just can’t get it to work the way I want.

First, the landscape:





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Now, theoretically, the grass should appear on layer A, but it doesn’t.

e.g.

Now, if I create a new layer called ‘grass’ and connect it like this

It works… but only if I paint the layer on top of my A layer. Which, as you can image, would mean I have to paint my ENTIRE LANDSCAPE. Tedious, at best.

So HOW can I get it to just auto populate my main layer?

As a side note, this is getting old:
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What do I need? More RAM?

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Pretty sure it isn’t my GPU

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