I’ve read in multiple sources that it’s possible to create tabs in the Project Notes Manager. However, I’ve not found a way to do it. Is this still possible?
Anyone? Anyone at all? Bueller? Bueller? 
In the Windows version you simply have to click the “+” button in the Project Notes window to create a new note and by this automatically a new tab. I would think that this is quite similar to the Mac version, isn’t it?
For the Mac - Project->Project Notes
Then in the notes window, click the “+” at the bottom left of the window. It’s not tabbed per se, but does provide a named list of notes. To remove a project note, use the “-” after highlighting the note to remove. Hope that helps.
The project notes window used to contain tabs, many moons ago, but the tabs were replaced by the sidebar list instead, which allows for easier management of notes.
All the best,
Keith