Thanks, but I am well aware of that setting and it's already set to open links in tabs instead of windows, but that only applies to links "passed in to" the browser, e.g., from the e-mail client or a desktop HTML shortcut, not links activated from webpages one is viewing. On webpages one is viewing, provided one is not in the List of Links dialog, activating a link via Enter will replace the content of the current tab and via CTRL+Enter will open it in a separate tab. All links directly activated from the List of Links dialog are exhibiting the former behavior and there appears to be no modifier key that can be used in conjunction with the "Activate this link" button to make it open in a new tab.
Try it out, you'll see the behavior for yourself.
Brian - Windows 10 Home, 64-Bit, Version 1803, Build 17134
Travel is fatal to prejudice, bigotry, and narrow-mindedness, and many of our people need it sorely on these accounts. Broad, wholesome, charitable views of men and things cannot be acquired by vegetating in one little corner of the earth all one's lifetime.
~ Mark Twain