Thanks for the clarification, Mark.
This splits into two features, both nice ideas, that are identified but still being spec'd.
1. Favorites/shortcuts. A set of UX enhancements facilitating access to frequently-used saved sessions. This could certainly include a popup option for the extension icon as you suggest.
2. Linked sessions. An option to open a saved session in a linked mode that automatically applies navigation and other changes in tab state back to the saved session. This one has some challenges related to managing expected behavior for establishing and communicating the boundaries of a linked vs non-linked session and reconciling (or perhaps preventing) direct edits to a saved session while open in a linked mode.