Link Opens New Window (Linux)

[borgward]

When I click on a link in an email (Thunderbird 53.4.0 for Linux Mint) It opens a new FF browser instead of a new tab in the current FF. (57.0 for Linux Mint) This also just happened when I clicked on a link at Help > About Firefox > What's New, so I do not think it is a Thunderbird problem.

[DanRaisch]

Try entering "about:config" (without the quotation marks) in the location bar and press enter. Then enter browser.link.open_newwindow.override.external in the Search field. Right click on the entry when it is displayed and change the value to 3 to have Firefox open links from Thunderbird and other external programs in new tabs rather than new windows.

[borgward]

Thanks. That worked. Why is FF doing this all of a sudden? I have been using it for years and never had this behavior before?

[DanRaisch]

Changes in the newest release made all legacy extensions obsolete, so it's possible that a setting has been changed in the new version or an extension which is no longer working had made a change that is now reverted to default.

[borgward]

FF is still opening links in FF to a new window even after I changed the value to 3

[DanRaisch]

Try creating a new profile and make no changes to it until you have tested to see if the issue is present there.
http://kb.mozillazine.org/Profile_Manager