Thank you for the review as well as for providing feedback. Regarding the requested features: I already have in plan to add support for multiple selection (soon) as for the saved tabs preview. I need to figure out a good solution for it, since bookmarks storage does not support adding additional storage information, real-time preview might not be as fast as it should and any kind of additional storage that's not inside the bookmarks API would be a little problematic for syncing and caching. I have some ideas but definitely is not something really easy to implement, but I can see why it would be helpful, so If I can find a good solution I will try to add this as well.
Thanks for using the addon.