@sadyphus strange, works as described on the addon page for me - you have to keep in mind that addons can not yet add their context menus to tabgroup headers, so you have to click on any tab inside of a group to unload it.
At the moment, in order to unload all tabs in a given group, you have to manually go through and unload each. It would be helpful if you could right click the group and simply click "unload all tabs" I often keep a group for tracking packages that I do not need to be consistently loaded but is still helpful to have in the tab bar, and this feature would greatly help.