Move viewers between tabs

[hbcarlos]

Fixes #21

Screencast from 04-26-2023 10:58:28 AM.webm

Moving between tabs works now, but here is a minor issue. Since we are not updating the document when moving/resizing an item, the tab gets rerendered every time we carry an item to a different tab. Hence, each item comes back to its original position. I can fix it in a new PR.

[github-actions[bot]]

:point_left: Launch a Binder on branch hbcarlos/glue-lab/fix#21_

[trungleduc]

Thanks @hbcarlos