I'm looking for a currently maintained Firefox add-on that provides:
- a grouping functionality with a "group tab" bar in addition to the tab bar,
- drag-and-drop of tabs between groups,
- an ability to rename tab groups,
- an ability to suspend/hibernate (unload) tab groups,
- correct session restore on browser restart, compatible with Firefox 29.
What I'm basically searching for is a replacement for the TabGroups Manager add-on, which is sadly no longer maintained.