If I enable vertical tabs on sidebar and move sidebar to the right, tab group colored line (that indicates tabs in a group) stays at the left, so its not at the edge of the screen but between tabs and page.
Since there is nothing between this line and page, it is harder to see the line on some pages. Also scroll bar makes it very hard to distinguish.
Moving this line to the other side (at the edge of the screen) would solve this, it would look like sidebar on the right exactly mirrored and it would be easier to see tab groups.