Vscode: Expose a dropdown on the sidebar for extensions

[chairy]

Expose a dropdown on the side bar (see screenshot) to extensions to allow users switch between views within a view container. This can allow an extension to scale as the number of views increases, without having the need for an extension to have multiple icons in the activity bar. It also keeps the number of icons in the activity bar manageable for the users.

@misolori

[kschaab]

Seems reasonable considering the number of internal extensions that extend ViewPane to get this behavior. Please extend this to external extension developers.

[BigMorty]

This is a feature we would really like to use in the Docker extension!

[russwolf]

Any update on if/when this is being considered? It would be a great way to enable extensions to scale without having to either 1) stack multiple views in the sidebar or 2) introduce multiple icons in the activity bar. Or do you have any other work planned to address the underlying problem? Thanks!