I agree that the tab closure should return to the parent tab, as outlined by @eirk . The current UX also does not work well when you have pinned tabs. For example:
- Pin a tab
- Pin a 2nd tab
- Open a 3rd, new tab (not pinned) and navigate to some website (say, google.com)
- Open a hyperlink from the 1st pinned tab
- Close the newly opened tab
Notice that now the tab focus is on the google.com tab. I would expect the focus to return back to the 1st pinned tab