Hi John, that sounds like the default setting and no changes should be needed:

• Untargeted links open in the same tab, unless an add-on directs them to open elsewhere
• Links targeted to open in a new window may be diverted to a new tab if they aren't coded with restrictions that make them look like a dialog (there is a setting you can change to force them all into a new tab instead)
• Links in external applications follow the targeted link setting by default, either opening in a new tab or a new window

Could you check these settings:

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

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

(3) Review/Edit the preference values as follows (double-click the current value to open an editing field, and then when you're done, press Enter or click the blue checkmark to save the change):

(A) browser.link.open_newwindow - for links in Firefox tabs

This is the one that has a checkbox on the Preferences page and determines whether targeted links are allowed to open in a new window or are diverted to a new tab instead; there's no effect on untargeted links:

• 3 = divert new window to a new tab (default)
• 2 = allow link to open a new window
• 1 = force new window into same tab

(B) browser.link.open_newwindow.restriction - for links in Firefox tabs

By default, if a page sets width, height, or toolbars for a popup, Firefox will open it in a "dialog-style" window. To force those into a tab as well, you can change this preference to 0, but that's not directly relevant to your question:

• 0 = apply the setting under (A) to ALL new windows (even script windows with limited features)
• 2 = apply the setting under (A) to normal windows, but NOT to script windows with features (default)
• 1 = override the setting under (A) and always use new windows

(C) browser.link.open_newwindow.override.external - for links in other programs

This preference governs those external links that open in Firefox:

• -1 = apply the setting under (A) to external links (default)
• 3 = open external links in a new tab in the last active window <= You could try this if -1 isn't working
• 2 = open external links in a new window
• 1 = open external links in the last active tab replacing the current page

To return to normal if things go haywire, there's an arrow-like reset button at the right end of each of those rows if it has a non-default value.

Was that different than what you had?

One other note: sometimes what Firefox thinks is your default profile and what you consider your normal profile get out of sync. External links open in your "default" profile rather than the one you are currently using. If external links are opening in a separate window that doesn't match your normal windows (e.g., different customizations), this could be the explanation.

If you suspect that, compare a regular window and an external link window in this area:

Open the Troubleshooting Information page using either

• "3-bar" menu button > "?" Help > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the first table on the page, on the Profile Folder row, compare the paths. One of them is your normal profile, and the other one might be set as the default. For now, the important part is the part after the dot, which could be something like default, default-release, default-longnumber or a completely different name.

In your regular Firefox, type or paste about:profiles in the address bar and make sure the profile you prefer is marked as the default. If it has a button labeled "Set as default profile" under it, go ahead and click that button to make it the default.

If it's already the default or that doesn't make any difference, hmm, we'll have to dig deeper.

Thanks for the replies. My settings were a little different. I set them all as defaults as you suggest, and now every click on a web page opens a new tab. (External links are opening in new tabs, which is fine.) This is the behavior that started at some point and what led me to monkey around with the config.

Do you have an extension like Open Link with New Tab or other tab-related extension? You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions. On the right side, find the "Manage Your Extensions" heading.

If there is at least one extension before the next heading -- "Recommended Extensions" -- please continue:

Cast a critical eye over the list below that heading. Any extensions Firefox installs for built-in features are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Anything tab-related or unfamiliar? If you see any you just do not remember installing or why, please disable (or remove). For your privacy and security, don't let mystery programs linger here.

Any culprits in there?

Holy cow, I did have that tabs add-on and that was the problem. I have no recollection of installing that. D'oh! Thanks so much!

John