Is there any chance you could add a feature to completely disable rendering the guide in blocks that aren't air or water?

With most blocks, it's not an issue, because the block itself hides the guide indicator.

But when working with glass or other transparent blocks, the indicator is visible inside the block, which makes it hard to tell at a glance whether a space is occupied or not.

Or if that's not possible, maybe a way to set the guide block size to fill the entire block? Then it's easier to see if a block is filled in or not because the whole block will be tinted red.

I'm making a large glass dome because my bees can not be trusted with free will.

Hi, sorry for taking a while, I completely forgot I had to reply to this.

Specifically hiding shape blocks where a block has been placed would break some optimisations, so I don't think that would work. However, hiding shape blocks in transparent blocks similar to how shape blocks are hidden in opaque blocks should be possible depending on how well Minecraft's render code cooperates.

Changing the block size should be trivial and I like customisation, so no issues there.

I've added them both to my list of things to do and I'll see if I can get them done sometime soon :).