Hi,
I have done this two times now without remembering it. So partly this is for future Nicklas:
In VS Code, It is very easy to accidentally and unknowingly drag and drop a button out of the activity bar and into one of the others.
In my case, I dragged it into the “Folders” button, and what then happens is that the subtasks of the “PlattformIO” button is added into the “Folders” button. And way down where you don’t see it if you don’t know where to look.
If you find it down there (or wherever), it it easy to drag it back.
But as it is easy to do accidentally, this won’t be what you thought happened.
Instead you start reinstalling things and start looking here and ask the community.
(BTW, this apply to all buttons on the activity bar, and might confuse not only the PlatformIO community)