Enabling Code Folding Bar in Xcode

How to enable the code folding bar next to the line numbers?

I googled "code folding Mac"; it's all about triggering code folding and unfolding, but nothing about enabling the bar.

I have tried using Editor -> Code Folding -> Fold/Unfold to fold and unfold codes, but I don't have the vertical bar there next to the line numbers; so, I have the button to click to fold and unfold.

How can I enable that bar?

Please see image here here .

Solution

I always encounter this that suddenly I accidentally hide the Code folding ribon. So from @PetahChristian's answer, I captured it with screenshot.

Xcode > Settings > Text Editing > Check "Code Folding Ribbon"

You may also access Settings through shortcut command + ,