Background and Mask not showing in Builder with Fusion

I’m in Davinci Fusion (just upgraded to v 18) and am having trouble getting the Sapphire Builder to work.
I added the S_Effect node in Fusion
I connected a Media node (video of a drone shot) to the background input of the S_Effect node
I connected a Media node (video of a hiker) to the foreground input of the S_Effect node
I connected a Text node to the mask input of the S_Effect node
In the Inspector for the S_Effect node I clicked on Edit Effect to launch Sapphire Builder

However, the ONLY thing that shows up is the drone footage when I click on the Source node in Builder. However, because of the way I set it up in Fusion, the HIKER should show when I click on Source, and the DRONE footage should show up when I click on the Background node. However, NOTHING shows up when I click on the Background node. Same with the Mask, which should be showing text (I’ve also tried importing a PSD file with text as a mask and that doesn’t work either).
I’ve also noticed that if I connect anything to the Foreground or Mask inputs of the S_Effect node, nothing works at all.
How do I get this to work?
Thanks

You must be using the Fusion tab in Resolve, which is not fully functional. It works the way you expect in Fusion Studio.