Hey ! If I have an instance with VisibleBarriers and LiteMatica, when I use my middle click on a block, an air block is systematically pickup preventing any other block from being taken.
This bug was tested with VB enabled and disabled.
After testing, if i disable the "pickBlockFirst" from litematica's config, the bug doesn't happen anymore.

I have this issue as well.

@SkyWors I'm not seeing a pickBlockFirst option in my Litematica config, are you sure that's what it's called? I do have easyPlaceFirst, but that's already disabled.

Sorry I wasn't specific enough, I was talking about the keybind of this name, if I disable it, the bug doesn't happen anymore.

I was talking about the keybind of this name

Ahhh, ok. Thank you, I found and disabled it now.

Unfortunately it seems another side effect of VisibleBarriers is breaking the easyPlace mode of Litematica, so I'll just have to disable VB for the time being.
Hopefully this gets fixed soon!

This is due to Litematica's RayTraceUtils calling BlockState.getOutlineShape without the ShapeContext parameter, which defaults to ShapeContext.absent(). VisibleBarriers then checks against ShapeContext.absent() and returns a full cube. This causes Litematica's raycast to hit the air block inside your face in the litematic mirror world, when raycasting for a pick block in the litematic. Because this counts as a "successful" raycast, it then cancels vanilla's pick block because it thinks a pick block has been successful from the litematic mirror world. To fix this, Litematica needs to use an EntityShapeContext instead of ShapeContext.absent(), and I've verified this fixes the issue.

This was fixed in litematica 0.15.3