Window(pane) focus and pinned notes

Obsidian 0.14.15
Windows11 21H2

Using the Obsidian Sandbox vault, I’ve opened and pinned all three notes in the Adventurer folder. I then click the first note (“From plain-text note-taking”) in the left sidebar and it opens in a new pane next to the same pinned note (now 4 notes are open, two of the same). Since “From plain-text note-taking” is opened and pinned, shouldn’t clicking that note cause Obsidian to switch focus to that note instead of opening a new pane?

Maybe I’m misunderstanding something simple or how pinned notes work.
Thanks for any wisdom.