Glad to see a WE having this feature. But some situations do not allow the back button to work properly. If I load a series of tabs from a folder in the Bookmarks Bar using the 'Open All in Tabs' feature, the WE does not work to close these tabs. I am hoping to see this fixed in the near future as its a great add-on for FF. Thanks again.

Add on now does this properly - thanks. One more thing if I open a site with no parents and hit the Back button the tab should close. That would be great! Love this app...