hi @QTom did you already completely shut down Cursor and then open a single project? You do not seem to be in a project from what I see in your screenshot.
It may help with the display. I use for long time vertical bar and it is still available.
There may be some other setting causing the issue.
Please check if View > Appearance > Primary Side Bar is enabled. (it can be set left or right)
Yes, I can only use Editor Layout for now; I originally wanted to position the Agent in the middle to focus on AI Chat, but this issue has disrupted me