You could bookmark this: about:preferences#security

Or you could keep it open in a tab somewhere, and use the "switch to tab" feature to find it when needed.

If you prefer to switch back to the old dialog for now, there is a way to do that.

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

(2) In the search box above the list, type or paste pref and pause while the list is filtered

(3) Double-click the browser.preferences.inContent preference to switch it from true to false

Note: I don't know whether that will be in Firefox forever or is a transitional feature. As you've probably noticed, the long-term trend is to remove things that pop up.

Jenna3 said

I would also like to know how to set up a default under "Accept cookies from sites" to "Never" for "Accept third party cookies", so I don't have to keep going back and selecting it each time under the pull down bar.

I don't understand this one. If you are getting an infobar sliding down between the toolbar area and the page about whether you want the current page to be able to set cookies, I think that is asking about "first party" cookies and not "third party" cookies. But I stopped annoying myself with that bar years ago, so maybe something has changed...

Could you describe the sequence of what you're seeing in more detail?

• Firefox > Preferences > Privacy > Firefox will: "Use custom settings for history"

You can allow third-party cookies only from visited domains.

• http://kb.mozillazine.org/network.cookie.cookieBehavior

You can set the network.cookie.thirdparty.sessionOnly pref to true on the about:config page to make third-party cookies behave as session cookies that expire when you close Firefox.