I have donated when the developer ask to help him to move to the new extension engine.
Until today, I do not see any progress in the development and only complaints from the developer.
Meanwhile I found some extensions that can partially replace the old and good TAB MIX PLUS:
Focus On Left Tab After Closing
Open Tabs Next to Current
Manually change configuration to allow always open new tab from address bar:
about:config -> browser.urlbar.openintab -> true

That`s all.