Hi!
Sorry, this is probably a super newb question, and usually it’s pretty easy to find an answer to this stuff online but I was at a loss for what to search for. Lines, transparency? What is this?
It happens to my subtools sometimes, doesn’t seem to affect them (I can still sculpt and change their topology and color etc) but I can’t figure how to turn it off, and it’s making my eyes hurt 
I know it’s probably really obvious but any help would be great!
Img attached.
You’ve probably got Polyframes on (Shift+F) while using Live Boolean.
Thanks for the prompt response Marcus!
I don’t appear to have Live Boolean on - unless there’s a sneaky extra way to enable it that doesn’t give any UI feedback? (The Live Boolean button next to Lightbox isn’t pressed). For reference here’s what the tools look like with polyframe on vs off. Still getting the strange banding.
It looks like you have subtools selected with the “Transform All Selected SubTool” option on the Gizmo 3D (see below image). It’s odd that on your first image it shows it as being off. Try turning it on then “Ctrl+Shift+click” on those subtools to deselect them then turn it back off.
That was absolutely it zber2!
Thank you so much! It looks like I’d toggled the select-multiple-subtools off, but the visualisation had stayed on. Flipping it off and on a few times then de-selecting those subtools worked great.
Thanks again! Can I rep you / mark this as closed?
No problem! Glad that fixed it for you. All is good. 
Thanks zber2!
You’re welcome Marcus.