Tabs Do Not Open In Current Group

This is related to my feature request, but is a separate issue

If the tab that the user searches from is the in a tab group, the search links open as tabs in the current group, as expected

However, if the searched-from tab is in the **last tab** of the group, they open in new tabs made outside of the group

Expected behavior would be: tabs open in the group of the searched-from tab (unless some other option is made available & specified, as per my feature-request)

Reproduce the search behavior with a tab in a group, comparing an ordinary group tab with the group's last tab. Trace the tab-opening path used by the search links and confirm that the fix keeps opened tabs in the searched-from tab's group, including when it is the last tab.

Written by the indexing model from the issue text.