What is your default setting for opening external links? Normally, it follows your internal link setting, but here's how to check:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.

(2) In the search box in the page, type or paste neww and pause while the list is filtered

Firefox will list several preferences.

• browser.link.open_newwindow => covers your typical link in a page in Firefox that is targeted to open in a new window, and "3" indicates to open it in a new tab instead
• browser.link.open_newwindow.override.external => covers links launched outside of Firefox, and "-1" indicates to follow the above setting for internal links

(3) To ensure that external links are directed to a new tab instead of a new window: double-click the browser.link.open_newwindow.override.external preference to display an editing field, and change the value to 3 then press Enter or click the blue check mark button to save the change.

Thanks for the quick reply!

I've tried out your suggestion, but it sadly didn't fix my issue. The command still opens a new window instead of a new tab, also tried omitting the `--new-tab` option, but it still does the same.

Hmm, I don't know why --search and --preferences open in a new window instead of following the default behavior for external links. The command-line interface isn't especially easy to research in the source code repository (https://searchfox.org/mozilla-release/source/), especially with common terms like those.