when tabs are set to open next to the current tab, Duplicate Tab duplicates the active tab, not the clicked-upon one

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Detailed steps to reproduce the problem:

  1. set "Add new tabs at the end of the tab bar" to "No"
  2. open three distinct-and-identifiable tabs
  3. make tab 3 active
  4. right-click on tab 2 and select Duplicate tab

What happened: Tab 3 was duplicated

What should have happened: the tab I right-clicked on is duplicated

If I set the pref to "Yes" the "correct" tab opens. I'm not running the nightly, so the recent change for #9994 (closed) might have already addressed this?