conex
This addon tries to replace some functionality from the discontinued *TabGroups* with some differences:

Differences to tabgroups

Global keyboard shortcuts

Conex popup keyboard shortcuts

↓ / Tab jump to next container or tab in the popup list
↑ / Shift+Tab jump to previous container or tab in the popup list
Enter on a tab: switch to tab / on a container: activate the last accessed tab of the selected container
Backspace on a tab: close the selected tab / on a container: delete selected container
→ / ← / Ctrl+Enter on a container: expand / unexpand tab list of the selected container
Ctrl+Shift+Enter / Ctrl+ + on a container: open a new tab in the selected container and activate this tab / in the search box: open new container dialog

Enable tab hiding

Necessary addon permissions

<all_url> : for taking screenshots for the thumbnails during search
activeTab (optional) : necessary in order to show a dialog, where the user can select the container to open external links
bookmarks (optional) : for searching in bookmarks
contextMenus : for context menu for moving tab to a different container
contextualIdentities : for working with tab containers
cookies : for working with tab containers
history (optional) : for showing history results in quick search
menus : for creating context menus when moving tabs
notifications (optional) : to show a warning if the tabhiding is not activated
storage : for storing thumbnails
tabs : for tab handling
tabHide : for hiding and showing tabs
webNavigation : for intercepting and reacting on new tabs
webRequest : necessary in order to show a dialog, where the user can select the container to open external links
webRequestBlocking : necessary in order to show a dialog, where the user can select the container to open external links