Yes! When attempting to close the last two tabs in the vertical tab list, one after another, the "Tab Closed ↩" popup of whichever tab you close first will arise at the bottom of the list and obstruct the close button ('X') of the remaining tab, for it's full 3 second duration. Hence, to close the last n tabs, you must close the second-to-last tab n - 1 times, and then wait those 3 seconds to close the last tab.
Ok I now understand what someone earlier was talking about. This is fixed in nightly, because the have a new open tabs representation. Also you can swipe the notification away, and you can close the tabs by swiping also (I'm never using those small close buttons).
I just checked this in nightly and the problem persists. Open at least ten tabs, set tab view to list instead of thumbnails, close a tab using the X on the right, try to select the latest tab (the one at the bottom). You can't because there's a helpful little "tab closed" notification.
