In "Expand in hover", remove vertical stack in the bottom for better UX

[HynDuf]

When collapse,

When expand,

• When it expand and there are many tabs which overflow the tab bar, the transitioning from vertical to horizontal will create a temporary dark section which will take a noticeable time to load in the tabs.
• One more reason is there is no point in displaying all 3 vertically, because in order for user to click, they have to move their mouse there and the tab will be expanded anyway. So just display only one and user will know where to look for it to click anyway.