It is undeniable that “vertical tab” feature was a hit since day 1, however, it becomes a little inconvenient when you have many tabs opened at the same time. These are some ideas to help this awesome feature to be nicer.
In my opinion, would be nice that it shows the Tab visible in top menu (like in horizontal tab approach) but only for the focused/current tab.
Add a close tab button (X) and an option (context menu) for the current tab at the top. This is a nice-to-have functionality, because we have to move across the whole screen until the left side and look for the tab. It's annoying .
Add a menu option to duplicate that tab on top too. This way we can duplicated the current tab easily and has it aside of original one (just 2 tabs maximum at top), while the rest of our tabs remains in the vertical tab pane.
Custom Layout. Allow to place the Vertical Tab pane to either left or right side of the screen.