Click on the word EDIT above the Top Site pane. There is the word edit and the "?", if you hover over the ? it pops up the pane that covers the word edit. In that case move your mouse away, then "come in from the left" until just over "edit", when you click that, you can add a 2nd row, and add sites you want on it. If there are site icons you want to stay on the top site section, hover over the icon, then click the 3 dots that appear. You can pin, remove, dismiss....etc.

Whoa, it worked. I'm not sure why I didn't try that initially, unless I thought it wasn't clickable. Thanks!

Fyi : Make top sites in tab page more (smaller icons) Copy/paste about:config into the address bar and press enter then is the top of that page copy/paste browser.newtabpage.activity-stream.topSitesCount into the search bar, I think I read you can double the number there from 6 to 12 to expand the amount.

Is not going to break anything if too many will not show. Just remember how to reverse this .

Please let us know if this solved your issue or if need further assistance.

Pkshadow said

Fyi : Make top sites in tab page more (smaller icons) Copy/paste about:config into the address bar and press enter then is the top of that page copy/paste browser.newtabpage.activity-stream.topSitesCount into the search bar, I think I read you can double the number there from 6 to 12 to expand the amount. Is not going to break anything if too many will not show. Just remember how to reverse this . Please let us know if this solved your issue or if need further assistance.

All you need to do to add more (12 instead of 6) is in the "Customize New Tab Page" just click on the "Show More" it will add a 2nd row, all same size, but now 12.

Pkshadow said

Fyi : Make top sites in tab page more (smaller icons) Copy/paste about:config into the address bar and press enter then is the top of that page copy/paste browser.newtabpage.activity-stream.topSitesCount into the search bar, I think I read you can double the number there from 6 to 12 to expand the amount.

You can also change that to 18 or 24 if want even more Top Sites. In addition to being able to manually add more top sites, I have found some other customizations that can be done:

To re-order your Top Sites: go to about:config, "accept the risk", then go to "browser.newtabpage.pinned". Now, you can edit in place, but I'd recommend copying the value to your favorite note editor, and making a second (backup) copy before you start changing things. Everything inside of each set of { } is one Top Site, so you can move them around, making sure to preserve the commas },{ and beginning/end brackets [ ]. Once you're done, right click on "browser.newtabpage.pinned" and select "modify" then paste your edited code and click Ok. (note: you'll have to restart your browser for the changes to take effect)

You can also change the display name of your Top Sites: same place as before, what you're going to do is after the "url":"http//etc." add "label":"My Label" making sure to preserve commas between attributes like so; {"url":"http//etc.","label":"My Label","baseDomain":"etc."}

One more note: while re-ordering Top Sites you may see some null,null those are unpinned sites between pinned sites, and you may delete them to move all of your pinned sites to the top (again, make sure to leave one comma between curly braces).