I'd like tabs to open next to the current page instead of next to the right-most tab; it's annoying to have to scroll all the way to the right when there are many tabs open (regularly in my case). I can't recall if this was part of Tab Mix Plus extension or not, but the add-on hasn't been updated for the latest version of Firefox. I really wish they'd add an option within the browser itself, but otherwise I guess I'm looking for a lightweight alternative to solve this specific tab-opening issue in Quantum. Any suggestions? The other thing is that in Firefox Quantum, using the mouse's scroll wheel to scroll along the row of tabs feels slower than in previous Firefox versions. Also, when clicking the "List all tabs" arrow at the end of the row, you can no longer right-click on a listed tab and close it, which I wish they'd fix.