I couldn’t find any info on this in the manual or forum here, so I thought I’d share a little trick I stumbled on.
You can lock the “hide invisibles” key-hold command (backtick/tilde key on my keyboard) by holding shift as you release the key. Then just press the key again to show invisibles.
I’m not sure if it’s an intentional behavior or not, but I was previously hoping this was a feature and was glad to accidentally trigger this.
Well, so much for trying to share a useful tip. In that case, please do consider an option for that key to have a preference to toggle instead of a temporary hold. Or perhaps a key command like Alt/Opt+backtick for a toggle.
Also beware that when you’re in this “mode”, you can’t see what’s selected, but Dorico still works as usual, so there’s a danger of accidentally doing something you can’t see.
Interestingly, I learnt the same trick in FontLab, from which Dorico takes inspiration for the use of this key/function, and Z X to zoom.
I rather like the idea of having the option of treating it as a toggle. To be clear, I like the current behavior where you hold briefly, but I could see a toggle being useful in some circumstances.