How do I set url's into the newtab page?
There used to be instructions on how to do this. I can no longer find them.
You can modify the browser.newtab.url pref on the about:config page.
In case you meant that you want to add thumbnails to the page which are not among your most frequently visited sites, for example, adding sites from your bookmarks, see this article for how to do that: Customize items on your Firefox New Tab page.
"Pin a site
Just click the pin icon in the top-left corner of the site to lock it in that position on the page. "
1. There is no "pin icon" on the page. 2. Lock it into that position on WHAT page. When I'm looking at the site page I can't see the new-tab page to tell it which position.
What is the current value of the browser.newtab.url pref?
If you set it to about:newtab then you get the built-in new tab page with the 9 (3x3) tiles that shown by default recently visited web pages.
If the new page is disabled then you see a faint icon in the top right corner tat you can click (browser.newtabpage.enabled should be true).
You can change the order of the boxes on the about:newtab page and drag an item to a different tile to pin it to that position or you can remove a website by clicking the close X to block that URL.
You can drag a bookmark or history item and drop them in a tile on the about:newtab page to pin them and have your own favorites sites showing.
Changes made manually on the about:newtab page are stored in the browser.newtabpage.pinned (default = [null]) and browser.newtabpage.blocked prefs that you can check/modify on the about:config page.
Start Firefox in Safe Mode to check if one of the extensions (Firefox/Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Firefox/Tools > Add-ons > Appearance).
- Do NOT click the Reset button on the Safe Mode start window.