Hi,
I figured it out, thanks to this post from TNM My faders are all transparent.. what on earth? - Cubase - Steinberg Forums. His problem was transparent faders, but same root cause as my problem – the visual disappearance of my tempo track. It seems there is a bug in Cubase 9.5 (for a few unlucky users) that causes these kinds of interface problems. What triggers the problems (if you are one of the unlucky ones) is if you save your preferences in File > Preferences > Store. It’s clicking on that Store button and creating a custom set of preferences that does the mischief.
If you have this problem, here is the work-around I use: I set my user preferences without storing them, but they are automatically saved in the project, so I don’t lose them for that project. However, I would theoretically have to set up my preferences all over again for each new project. I found that I can make project templates that have my saved preferences in them, so if I start each new project with a template, it has my preference settings.
You need to manually reset your preferences to default in order to get rid of the corrupt preferences file. Just switching to Default in Preferences doesn’t do it. I found my preference file at c:\users_______\AppData\Roaming\Steinberg\Cubase9.5_64\UserPreferences.xml and renamed it.
Zaffer