I'm also adding a separate comment as a bonus, because this may open yet some other cans of worms and I want to keep it separate from the original one, so please bear with me: As for the universal/document layers themselves, and their visual manifestation in the Studio UI, any layer sitting above the topmost artboard could automatically become “universal”… because it technically already is. That is intuitive for any user to grasp, but some extra visual feedback – like, say, change its descriptor in the Layers panel from “(Layer)” to “(Universal Layer)” … and maybe even rename the current artboart-level layers into “(Artboard Layer)” for good measure – would also be very welcome and help a lot with discoverability. But if you want to go the extra mile and make sure people instantly get it without having to create and move layers around, you can also add a draggable separator with an independent scroll field, kind of like the one between Master Pages and regular layout pages in InDesign and APub. If you dragged layers and objects below the separator, they could automatically snap into the nearest artboard (since with the concept of universal/document layers, it would no longer make any sense to have universal/document objects sandwiched between different artboards in the layers panel like they do now, and with the “Automatically move objects…” behaviour activated, they could just jump to the topmost layer in the universal/document section when dragged, in the actual WYSIWYG document working area, from their current artboard onto the pasteboard). Boom!, instant reconciling of both Affinity's new and current artboard-centric layer model and Adobe's/Corel's/Macromedia's document-centric one, without having to add an extra Artboards panel like Adobe did. That should make a lot of people happy without cluttering the UI too much. Also, you could extend the concept to Affinity Publisher, and thus even allow for document-, master page- and layout page-level layers, in a totally logical and consistent tie-in with the Designer Persona. That would actually make Affinity superior and more flexible than Adobe's offerings.