First, open “Firefox.” In any window, click the “Firefox” menu button (three horizontal lines) and select “Add-ons” from the menu.

In a new tab called “Add-ons Manager,” you will see a list of all the Firefox extensions you have installed. Locate the extension you’d like to use in Private mode and click the ellipses button (three dots) beside it. In the menu that pops up, select “Manage.”

After clicking “Manage,” you’ll see more details about the extension on a special page. Scroll down and locate the “Run in Private Windows” option. Click the radio button beside “Allow” to enable the extension in Private browsing mode.

After that, go back to the last page and repeat these steps with any other extensions you might want to use in Private mode. When you’re done, close the “Add-ons Manager” tab. The next time you open a Private window in Firefox, the extensions you enabled will be working as you’d expect them.

If you ever need to disable an extension in Private mode again, revisit the extension’s “Manage” page in the “Add-ons Manager” and select “Don’t Allow” beside the “Run in Private Windows” option.