Traditionally:
- the ➕ appears to the right
- when clicked, the new tab is added at (or immediately adjacent to) the point where the click occurred.
With tabs to the side in 1.34.0:
- when ➕ is clicked, the new tab is added away from the point where the click occurred
- when the sidebar is collapsed (after using the shrink icon at the same level as the plus sign), the ➕ is easily misinterpreted as an expansion icon – this bugged me on scores of occasions over an extended period, it's not easy to learn to ignore the icon at which I point
Suggestion
➕ should appear at the foot, not the top, of the sidebar.