Keyboard navigation causes glitches in the sidebar

[domyen]

Describe the bug
When I use the keyboard shortcut to switch between components opt + up/down arrow I see two bugs:

1. The shortcut loses track of which component I'm viewing
2. The sidebar "jumps" around by scrolling back to the top before focusing on the correct position.

To Reproduce 1
Steps to reproduce the behavior:

1. Go to live storybook on next here
2. Press opt + down arrow to navigate through components
3. Continue pressing opt + down arrow (you have to do this for 10+ components to see the bug)
4. The position of the currently active story will reset and you'll end up focusing on the top component again

To Reproduce 2

1. Go to live storybook on next here
2. This will take you to one of the stories deep in the sidebar
3. Press opt + down arrow to navigate through a few components then press opt + up arrow to navigate back up
4. You'll see the sidebar start to jump around. In some cases you will not see what's currently selected in the viewport.

Expected behavior
For the sidebar to keep track of the currently selected component and for the scroll position not to jump around.

Video
https://www.loom.com/share/34a79ff8ca2345289abcfbda15fa4cdd

[shilman]

w00t!! I just released https://github.com/storybookjs/storybook/releases/tag/v6.1.0-rc.2 containing PR #13097 that references this issue. Upgrade today to the @next NPM tag to try it out!

npx sb upgrade --prerelease

Closing this issue. Please re-open if you think there's still more to do.