New panel button on the right of the panels bar gone - Safari

So out of nowhere the plus button to add a new panel that used to be at the very right of the opened panels bar in Safari is gone and I have no idea why.

Also I used the bar used to be there when I only had one panel open, but now it only appears when there's at least 2 panels open.

I do not understand what happened, but I'd really like to go back to how it used to be, my muscle memory is freaking out.