Strange no note head in trill

[meixner]

@joakimsandgren

wow…
this must be because I needed an “none” notehead and tried to solve it.
I see in the harp that these glissandos still have the “none” notehead even if I put back this default notehead.
what I don’t understand is how I can do a whole score “without” the default black notehead. what are all the noteheads in the score ? from where do they come ?

I’m quoting @johnkprice here from this thread which cleared up similar problems I had with Note Head Sets:

@johnkprice

The first rule of working with notehead sets is never modify a notehead with a name you didn’t invent. When you go to Library > Notehead Sets, select a factory-supplied notehead set in the left column and click the button New from Selection, you create a new notehead set containing a collection of factory-supplied noteheads. If you modify one of these noteheads, you get a red triangle warning that this notehead is now modified in every notehead set in which it appears. To avoid getting a red triangle, follow these steps:

1. Select the factory-supplied notehead in your notehead set that you want to modify.
2. Memorize its name.
3. Click the New from Selection button in the second column to make a copy of this notehead.
4. Give the copy a unique name.
5. Click the Edit Notehead button and modify the copy.
6. Search through your notehead set until you find the notehead with the name you memorized in step 2.
7. Click the Remove Notehead from Set button. This button looks like the letter U with an arrow coming out of it.