UI for toggling addons panel

[shilman]

Currently it's possible to show and hide the sidebar with a UI thanks to #15369

Among other things, this makes the sidebar discoverable if it gets accidentally collapsed via a toolbar shortcut.

We should have the same thing for the addons panel, esp. since there might be a long-standing bug that hides the addon panel

[Tomastomaslol]

Hi @shilman!

Would something like this work?

Kapture.2022-01-18.at.19.11.47.mp4

Is there an icon that is used to describe the addons panel?

[shilman]

@Tomastomaslol Awesome! I think we have a design in mind for this. @MichaelArestad can you share a screenshot?

[Pepijnk12]

I would like to work on this. Is the design ready?

[MichaelArestad]

Alrighty. Sorry for the delay.

Let's add an IconButton to the toolbar just to the left of the full screen icon.

1. The icon should only be visible when the addon panel is closed.
2. The specific icon change to reflect that last known dock state of the addon panel (right or bottom). If we don't know the last state, it should default to the bottom.

Screenshot

Icons proposed

1. bottombartoggle
2. sidebaralttoggle

[Tomastomaslol]

Thanks, @MichaelArestad! I should be able to open a PR fairly soon.

[Tomastomaslol]

@MichaelArestad @shilman

I just opened #17714. Please let me know if you like the implementation and if there anything i can do to improve the code! :)

Kapture.2022-03-15.at.18.37.33.mp4

[shilman]

Egads!! I just released https://github.com/storybookjs/storybook/releases/tag/v6.5.0-alpha.50 containing PR #17714 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.