Vlad Sorry I forgot about this during past weeks because of my semester exams,

there are some nitpicks 🙂
in the (ctrl command 2) show vertical tabs (maybe this has to do with some people turning the horizontal tabs off by default) it fails to activate sometimes and shows the windows menu sometimes. Usually it does the correct thing in the second activation (i tried both the menubar and via the shortcut) but I don't know where that one activation goes sometimes.
edit: found the issue 🙂 it's with animation delay of horizontal tabs during the activation of shortcut, but when you only have one tab it leaves no feedback and seems ignored.
some other things I noticed.
show bookmarks tab switches to vertical tabs view instead of closing the sidebar when activated again (maybe this is a choice but I think someone can also say it as an inconsistency)
recording of side menu transitions with one tab
with two tabs
my thought is that there is no need to switch to horizontal tabs with that command since it kind of breaks the flow.
another thing that is kind of annoying is you can only resize the sidebar for the tabs view and it resets when switching to window, bookmarks, or reading list.
this is all that I have noticed during the time I spent with some handy shortcuts with sidebar. will update if I found anything. again sorry for the delayed response