I didn't like the vertical tab and the icon is on a very and desgusting place. Everytime when I touch in the corner, to back to the first tab, I open the useless (for me) vertical tabs).
I really hate this icon and I'd like to hide that one, but I didn't find the option in everywhere.
"Enable Swipe to ShyUI" Set to disabled
"Enable Fullscreen Dropdown" Set to disabled.
Hopefully Vertical Tabs icon is gone for you.