Tab Control

A very simplistic add-on for Firefox to position new tabs to the right of the current tab and activate the tab to the left when closing the current tab.

Easy to use, no need to configure anything.

No permissions required.

Inspired by the old Tab Control add-on by Angly Cat that is not supported by Firefox anymore. This new add-on is built using Web-Extensions API that is supported by the most of the modern browsers, but it might be irrelevant for other browsers or not even work.

Known issues

• The browser.tabs.insertRelatedAfterCurrent and browser.tabs.selectOwnerOnClose settings have no effect when the add-on is enabled. If browser.tabs.insertRelatedAfterCurrent is set to false (non-default value), new related tabs may briefly appear at the end before being moved to the correct location. Also the tab, that would have normally been activated when the current tab is closed, may be activated briefly before the add-on activates the correct tab. I believe these effects are results of the Web-Extensions API limitations.
• The add-on may behave unexpectedly when used with any other add-on that moves tabs around on tab open and close events.
• Firefox makes tabs that are being manipulated manually active automatically. The tabs might be also opened, closed, moved (including between windows) programmatically by other add-ons and user scripts. Such interactions are considered in the implementation, but were not tested extensively.

Are there any alternatives?

Yes, there are:

• Tab Open/Close Control by F. Kolbe, that includes a lot of options, but sadly activating tab to the left on close was not working properly and the author hasn't released any updates for several months, which has prompted me to write this add-on.
• Open Tabs Next to Current by Sebastian Blask, that does exactly what it says in its name. Shame I haven't discovered his add-on before I went to lengths to implement my own.
• Focus On Left Tab After Closing by e10s, that I have not tested yet, but it could work in conjunction with the previous add-on.

License

This add-on is released under the MIT License. See LICENSE.md for details.