The Media panel in "Tools > Page Info" is only present if there are media files on the page. Your screenshots show a text/html file, so I'm not sure if this is an HTML page and if this page has media file on it. Does this also happen on a page that has real media content? Start Firefox in <u>[[Safe Mode|Safe Mode]]</u> to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem. *Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance *Do NOT click the Reset button on the Safe Mode start window *https://support.mozilla.org/kb/Safe+Mode *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes