Right now, the vertical tab menu hides the macOS traffic light buttons.
Not only does this look bad, it actually hinders the functionality of the browser.
I would suggest that when using vertical tabs the traffic light buttons should be incorporated in to the menu. This would be especially helpful in focus mode, where the buttons are hidden by default:
This would look better, more polished, and make the browser easier to use. It should only enhance extant workflows.
Zen does this very well.
Collapsed mode:
Not-collapsed mode:
The user will be able to access the traffic light buttons either with the fixed vertical tabs or within the collapsing menu. This would replace the buttons that the menu otherwise obstructs
