I’m almost certain I overlooked something quite obvious, but I can’t find a solution at the moment.
I have (quite) a few noteheads hidden (by changing the color setting in engrave mode), for glissandi etc. Works like a charm. Alas, when I print the layout (export it to PDF), the hidden notes show like I never touched that color setting. What am I missing?
Are you exporting Mono or Color? If you’ve hidden items using the color property, you have to export as color.
Alternatively you can create a noteheadless notehead set - there are steps for creating a notehead set here. For noteheadless noteheads, it’s a good idea to include something in the notehead itself so that you can still select it - a bit of text that’s just several Spaces (press the Spacebar a few times then add that as a glyph) works quite well.