Rated 5 out of 5 stars

Would be good to have an option to open in a new tab without loosing focus on actual tab.

Thank you for this very simple but useful extension.

This review is for a previous version of the add-on (1.0.1). 

Thank you for your feedback.

Changed to restore the active tab by holding down the shift key and opening the link (because it requires more program code if it is an optional item ...).

The new tab becomes active for a moment, but by immediately activating the original tab, it looks like it has opened in the background.

This is because there is a setting that is not activated when opening a new tab, but Thunderbird always opens it in the active state whether it is a specification or a bug.
https://webextension-api.thunderbird.net/en/91/tabs.html#create-createproperties

Sorry for the machine translation.