When using Safari’s Tab Group, there’s an annoying behavior that it always opens external link in a new window’s new tab instead of in an existing tab group. Specifically, a new Safari window will prompt out when clicking some links in Mail or other Apps.
There’re quite a few Safari settings that won’t fix it. Even someone wrote a Keyboard Maestro Macro to merge the tab into existing one. But actually, there is an elegant way to make it work.
The core issue is that there’s no default tab group to be configured in Safari to be the holder of the new created tab. However, the Focus setting does. Therefore, going to the Focus pane of Mac System Settings, creating a new profile to enable it with Schedule, and adding a Focus Filter of Safari that open external links in the chosen Tab Group.
Then it is, external link will open in the target tab group, and it will even automatically adapt to the current Focus scenario. Really weird place of configuration!