I like the idea of this addon, but the developer needs to expand the possible actions you can do with multiple selected tabs.

Opening all of them in a separate window is great, but for me it would also be really great to be able to create a set of bookmarks for these as well. I used to use Tab Mix Plus and the biggest advantage for me was the "Open Closed Tabs" function and a session manager where you could save a set of tabs to reopen later.

How would that work? After you'd picked the tabs to save and selected "Save to Bookmark Set" (or equivalent) You'd be asked for a set name. and the addon would create that a folder by that name under a certain bookmark folder (maybe predetermined, or the user could set this up to a default location, so that it could say, be under the bookmarks toolbar) and add bookmarks for each tab selected. Those could then be edited if needed like any other bookmark.

Just an idea.