Hi Difficult to answer this one as you are not comparing like for like on both systems and we do not know what this website editor is. I strongly recommend you update Firefox to get security and stability fixes as well as new features. You can read more about how to update [https://support.mozilla.org/en-US/kb/update-firefox-latest-version here]. You may wish to try Firefox Developer Edition, a version of Firefox that comes complete with a suite of web development tools. You can read more about Firefox Developer Edition [https://www.mozilla.org/en-GB/firefox/developer/ here]. I hope this helps, but if not, please come back here and we can look into a different solution for you.