I don’t know if you have resolved your issue yet or not, but today I also looked into the tutorial and got stuck at the same part, the “Text Block” isn’t exposable, at least it is not letting you click on the “eye” to expose it. So I jumped on the internet and found your post/ question. This problem only seems to be a graphical/ engine bug, just click “save all” under “file” and close the whole project. When opening it again, the problem should be resolved, it still doesn’t let you click on the “eye” to expose it, but when you look into your “UI_MainMenu” (just like in the tutorial) you can check each button, and under “Default” you should be able to change the text of every button, that you have dragged into the vertical box.
I follow a German streamer (“The Sky”), as I am German and he regularly live streams his work, thus I thought, it could have been an engine bug, as he encountered them every once in a while.
You can get worked up about bugs like this, so I hope this helps, even if I am a little bit late to the party. It might still help people who will check the “Common UI” tutorial at a later point and run into the same issue.
kind regards
Justin