Firefox's native behavior is:
- Open related tabs next to current (e.g., from a link in the current tab)
- Open new/unrelated tabs at the end of the bar
There are now preferences to manage both of those:
(1) In a new tab, type or paste
about:config in the address bar and press Enter/Return. Click the button promising to be careful or accepting the risk.
(2) In the search box above the list, type or paste
curr and pause while the list is filtered
(3) Then set:
Open Related Tabs Next to Current, Others at the End of the Bar:
browser.tabs.insertAfterCurrent = false (default)
browser.tabs.insertRelatedAfterCurrent = true (default)
Open All Tabs Next to Current
browser.tabs.insertAfterCurrent =>
truebrowser.tabs.insertRelatedAfterCurrent =
whatever
Open All Tabs at the End of the Bar
browser.tabs.insertAfterCurrent = false (default)
browser.tabs.insertRelatedAfterCurrent =>
false
To switch a boolean-type preference between true and false, double-click it.